for me it feels much smoother.  i cant actually notice a difference for my eyes but it has a different, better feel.  and then there's ssbm where i can actually notice whether i was a frame off.

60 fps side by side with 30fps looks far better.
games can really benefit from 60fps - but 30fps is still playable.
Many PAL region games ran at 25fps or 50fps. 50FPS is great -25fps is OK though.
PAL is vastly superior to NTSC - especially for movies as with pal you dont get any of the Image Jump which is associated with NTSC. Because with PAL thay run the 24FPS movies at 25FPS so there are no motion artifiacts at all - also it takes 4% less time to watch the same movie - thus saving valuable time.

Anything less than 25FPS is not worthy to even consider playing in my opinion.

It means I would have to draw Twice the many frames in an animation!!! which really sucks... even 24fps for an animation is a lot.. It's reaaaally boring... I'm in the middle of a project with luckly 12 fps.. bleh.. 60fps... When I'm finished with that 1 second I could have drawn 5 sec in 12fps.. I'm a graphic Designer/Animator.. :)

my average fps when i play ut2004 online is 12, sometimes its more but occasionaly it drops to 2 or even 1 0_0 it all depends on where i look which pisses me off cos i still play it regularly.

30 is fine, as long as it's not a certain Wii game... (just kidding, I'm looking forward to that game)

Seriously though, 30 is fine.

30 is more than enough for me ... but then nothing beats playing Tekken DR at 70 fps :D Still except some extra feeling of speed it doesnt bothers me to play games at 30 fps ...

30fps is fine.
60fps is nice to have though.

30fps is really all the human eye can handle so really as long as you don't get to a point on a game that is heavy intensive on the graphics then no worries on 30fps. 60fps on the otherhand is just nice to have.

None whatsoever

nothing for me, my eyes are too f***** up for 60/30fps to make a difference.