Lets see, I don't think I updated my list in awhile so I'll post my thoughts as well.
1. Anderson Silva +- (When you dominate two weight divisions and being as well rounded as he is you get the #1 spot)
2. GSP +- (A great win over Penn makes GSP a strong challenger for that #1 spot. But I see Silva facing and beating tougher competition in the near future)
3. BJ Penn +- (Gotta give Penn the nod over Fedor here since he's facing the top guys in his division and will soon clean it out and that's what its about. To be considered a current P4P best it starts with actively dominating your division first and foremost)
4. Fedor - (Possibly the best champion in our sport and he could probably clean out the HW division if he wanted to. But, there's a big difference between probably and actually setting out to do it. So while he's no doubt the best HW in MMA that doesn't give him a pass from fighting against the best. Until he gets in there with the best again with so many other elite fighters on the rise his spot may continue to fall)
5. Machida + (undefeated and has fought the best of the best. Controversial win over Shogun, but it still has to be considered a win nonetheless)
6. Shogun + (Will swap places if he wins)
7. Jose Aldo +
8. Rampage -
9. Cain Velasquez +
10. Jon Fitch -
Just for reference here's my previous list - I believe this was from August
1. GSP
2. Anderson Silva +
3. Fedor - (Hasn't fought since Jan and a possible win over Brett Rogers doesn't do much for his stock)
4. Machida +
5. BJ Penn
6. Big Nog + (hard to put Nog over Penn right now since Nog is not the best in his division, he needs a few more solid wins to move back up the ranks IMO)
7. Rampage -
8. Shogun +-
9. Torres
10. Mike Brown
Trying to keep them somewhat weighted I guess you could say - so basically Big Nog previously being 6 and Cain whippin that ass, on top of how good he is gets him the #8 spot on my updated list. As mentioned there as well Fedor's stock was already dropping so after a tightly contested fight with a green Rogers and not having any fights coming up assuming until the Summer, yes Fedor drops to #4. But, lets be honest when you look at Silva, GSP, and Penn are those three not the most well rounded fighters in MMA right now? Aren't they facing all of the top guys in (and out) of their division? Those three deserve the top spots.