After looking over all 30 suspects that were revealed to viewers leading up to the season finale of The Mentalist, I present my very own list of 7 suspects.

I originally narrowed down the list by deleting the following 12 people for several reasons (I only listed the most obvious ones due to time constraints):

Asher Maclean - He has been gone from the public eye for too long, and he wasn't a compelling enough character to be Red John
Doc Dugan - Ditto for Doc
Glen Snow - She helped somebody fake their own death, and Red John would not have done so.
Donny Culpepper - Red John would not take risks such as burglery, or cover it up like Donny did.
Gabe Mancini - Too obscure, as well as only becoming involved in the past season.
Walter Mashburn - He's a fun guy, and Red John has more important things than hedonism to engage in (however, the fact that he slept with Lisbon intrigues me somewhat)
Tommy Volker - He was caught doing other illegal things.  Even if he separates his business killings from his Red John killings as they are different he would never allow himself to be caught doing them.
Tolman Bunting - Do I need to explain?
Royster Daniel - Ditto.  Tolman and Royster were never intended to be involved with Red John. Ever.
Reede Smith - Same reasons as Gabe
Vint Molinari - I struggled a bit over what to do with him, but ultimately figured that since Vint helped bring Kristina Frye back, he probably didn't have much to do with her disappearance. 
Richard Haibach - Interesting character, but he just doesn't have anything to do with Red John.

That left me with 18, so I had to do a little bit further digging.  I ended up getting rid of Paul Fricke and Don Henderson before I continued on, however.  Fricke isn't of the Red John mold, and Don seems to serve a purpose and not do more than that.  Red John doesn't necessarily need to stick out to those around him, but Don doesn't even resonate with viewers for longer than the episode he guest stars in.

16 left, and I got rid of the following to narrow it to 10:
Sheriff McAllister - He intrigues me, but it's been so long since we saw him last, I feel like the direction of the show isn't headed this way.  Just a feeling, but a strong one.
Linus Wagner - I can't believe Red John, as a human being, would allow himself to be imprisoned for as long as Wagner has unless he had an endgame in mind that counted on his imprisonment.  Wagner could be Red John, but of the 16 left, he is the most unlikely.
J.J. LaRoche - The biggest (no pun intended) argument against LaRoche comes from this last episode.  Red John would not have backstory such as was presented for LaRoche, and if Red John was LaRoche, he would have had the ability to find the tupperware container through means other than Patrick.  He says he should have known Patrick would have told LIsbon, and yet he also seems genuinely upset that people know about it, for shameful reasons, not for dodging crimes reasons.
Dean Harken - Super unmemorable character, and thinking back about him, he just doesn't seem to have the temperment of Red John.
Osvaldo Ardiles and Gale Bertram - Isn't either of them because of the mole situation at the end of season 3.  If they were Red John or had anything to do with him, they would have been able to contradict, at the very least, if not override the information that was leaked to the real mole.  The assassin would then have gone to one of their rooms instead. 

This leaves 10 characters whom I all believe have considerable possibility to be Red John (in spite of my above reasons, I also believe Bertram to be of considerable possibility, but that is a hunch/desire more than anything).  Of these 10, I thought these 4 were less likely than the other 6, and thus after I give my reasons against these 4, I will give my reasons for the other 6.

Brett Stiles - This dude is into some serious stuff, but I don't think it's him for a variety of reasons.  The biggest one is that he was willing to be arrested and put under police scrutiny to find out which of his staffers was trying to unseat him.  This makes sense for him to do as the head of Visualize but much less sense if he was both the head of Visualize and Red John.

Ellis Mars - He lacks continuity as a character.  Just watching him feels like he was dreamed up for the particular episode in which he serves and then was discarded, and why not?  But, if he shows up on Patrick's list of 7 then I would go back and rewatch that episode a few more times, just to be sure.

Markham Shankar - This is my underdog selection, as I'm very surprised myself that he made it this far into my investigation.  He isn't compelling, and, like Ellis Mars, serves a very small purpose and that's it.  However, if he's on Patrick's list then he deserves another looking into, and I personally feel like he has the personality to be Red John.

Ray Haffner - He's in Visualize, and his discussion of it with Lisbon seems kind of interesting.  Neither damning nor absolving, which is exactly the feeling Visualize gives all too often. But I can't see him as Red John, and since he's been in CBI for just as long as Red John has had a mole in CBI, if Ray were Red John, he wouldn't need to have a mole in the CBI, and having one would put himself at more risk of being discovered if the mole knew of Ray's identity.

My list of 7, counting down from who I least suspect it to be to who I think it is:

7. Gale Bertram - I know, I know, but I just have a feeling that despite all logic, he may have something to do with Red John.  He's my number 7 choice though, give me a little credit here.
6. Jason Cooper - Red John is connected with Visualize in some way.  Perhaps this is it.  Cooper doesn't appear to have the temperament to be Red John, but he does have a connection to Brett Stiles, and further, Stiles doesn't get rid of him even though Cooper seems to be poised to take his place after Brett goes to jail. If it is Cooper, Stiles knows it is Cooper and they appear to have enough of a mutual respect for one another that Stiles would not throw Cooper out the door.  I also can't see Red John taking a backseat to Stiles in the chain-of-command at Visualize unless he was content to let Stiles run Visualize but do Red John things himself.
5. Judge Manchester - We've seen him recently, which is a good thing for whomever is Red John.  We know that he has quite a social circle, probably one of the better known socialites in the show, actually, and this characteristic is true of Red John also. "He is ma - " of course, fits the bill. He made sure that Patrick kept the Red John case, in spite of the FBI involvement.  I like Manchester, but he just doesn't have that extra umph that I feel Red John has.
4. Brett Partridge - He was my hands-on favorite to be Red John at the beginning of the season.  Then we were introduced to Kirkland and I gave it more thought, and while he is still one of my favorites, I believe his prospects have dwindled.  It is poetic that he was introduced in 1.1, and it also is intriguing that he has been at Red John copycat crime scenes.  It is also interesting to note that he was exclusively at copycat crime scenes, and NEVER in any other episodes until this season.  The implication is that Red John and Patrick, though they have met, don't get along.  This is the case of Patrick and Brett. There is also the voice similarities between Red John in the season 2 finale and Brett.  All of this says that Brett was going to be Red John from the beginning.  I believe that is the case, and I can't say I believe they changed their minds, but they may have.
3. Robert Kirkland - There is almost too much to say about Kirkland, but he is definitely up to no good.  The biggest bit of evidence for him to actually be Red John is his beside conversation where he asks, "Do you recognize me?"  All other evidence suggests he is a scapegoat, and that question can be answered by Kirkland's implication in some other, random crime.
2. Virgil Minelli  - I switched from Brett to Virgil when I realized when the suspicions and eventual appearance of a mole began; it was after Minelli retired.  Gregory Itzin is also a stellar actor and I believe he would be a great fit for Red John.  Lastly, the reason for the retirement was the discovery of Rebecca as an accomplice of Red John and her murder of Basco and his team.  She is later killed after passing by somebody who had business being inside CBI, which, as of the middle of the 2nd season, narrows down the list of suspects considerably.  Her smiling at the person she passes indicates that it wasn't some random person sent to kill her, it's either Red John or whomever she knows as a connection of Red John.  However, the nature of the smile says Red John, and that means that of my top 7, only Minelli, Bertram, and Manchester have scientific clout to pass so close to her so unnoticed as the killer undoubtedly does.
1. Max Winter - I place Winter as my current suspicion of who Red John is because of body language, empathy towards Patrick, intelligence on how to both commit a murder and get away with it, and Jack Coleman, who makes an excellent bad guy.  He exhibits body language and speech patterns identical of Patrick.  He also shows a deep knowledge of how Patrick is feeling.  He kills a man and gets away with it, even though police knows he's guilty.  And there's something about just watching him that screams Red John to me.

Can't wait to watch the season finale in 6 days!

Does anyone else have a gut wrenching feeling about Kirkland? 
All of a sudden, Homeland Security wants to be on the Red John Investigation. They are supposed to deal with mainly terrorists, so why the fascination with Lorelei and RJ? Kirkland wants to squeeze every bit of information from Jane that he can about his knowledge of RJ. 
Maybe this is all just circumstantial but I still have a really bad feeling about him