Fenixp: I'd definitely go for 60 FPS, combat does require some fast reactions regardless of your input method (and I actually am using a pad to play the game). That being said, every time I set foot in Novigrad my framerate drops to like 45 and there's one particular locations in Novigrad (around Triss's house and the hospital) in which my framerate inexplicably drops to 20, which is the worst performance I have ever seen of this game. Perfect 60 out in wilderness tho. Strange. (well not really given the number of actors in Novigrad, but god damnit, the place where I get massive frame drop is not even that busy)
The game don't require fast reactions IMO. Ennemies are quite predictable. And with 30fps you have an information every 1/30 sec (obviously), which means every 0,033 sec. That's not bad.
In 60fps you get an information every 0,016 sec.
So when you have 60fps, an information can be displayed 0,016 sec faster... Meh.
It can surely make a difference in some extremely fast games, but not here IMHO.