I can definitely see GSP winning again, but I wouldn't count Hughes out. If Hughes can get it through his thick skull that he punches like a rock'em'sock'em robot, then he'll focus much more on the takedown. I know he tried a couple takedowns, but I'm not entirely convinced they weren't a bit halfhearted due to frustration with his standup.
Next fight, Hughes will be prepared for a guy who is every bit as strong as he is, and who can end the fight multiple times due to punches, high kicks or even the leg kicks that dropped him. Hughes will have to get GSP down and work a ground 'n' pound to either get a stoppage or set up a submission. Still, I think GSP holds the definite edge due to both natural athleticism, super stand up, and a well rounded game.