I'm a huge GSP fan. As for who's on the horizon, I'm sure BJ could give him a good go, but GSP has to much momentum now in my opinion. In Pride, not too sure actually who could come in to challenge. It's the 170 weight class, and if I'm not mistaken the Pride Middleweights are 205 lbs (=UFC Light Heavyweight) That's why Wandy is always calling out Chuck Liddell.
As for Matt Serra I don't think he'll come out on top. Not in the slightest, but he should still give a decent fight. I like that guy a lot, he's an awesome team player and a good leader IMO. He gets a thumbs up from me.
Oh and did anyone catch the convo to St. Pierre in the ring? They told him they want his first title defence to be in Montreal! That'll be worth flying out for!
Too bad for Monson. I guess just having all that weight on him just sapped all his strength. But I've been dreaming of it for a long time, a Tim Sylvia VS CroCop / Fedor. I'd pay a hundred bucks just to watch that on an Ipod.