I don't really like the majority of graphical smilies. As Roph said, the more unique ones which aren't simply an attempt to reproduce the essence of an ASCII smilie are sometimes good. Some of the ones GFF has are really creative.
It also depends on the images that are being used. I've seen both good and bad graphical smilies. Some of them are really expressive, but they just aren't in the majority. The AIM smilies are some of the worst I've seen.
When it comes to ASCII smilies, I prefer the horizontal style smilies to the older vertical style. I don't really know why. I never liked the basic

smiling face to begin with, although it was sometimes necessary on Usenet. You can't always read for tone, of course. Faces like ^_^ on the other hand seem a lot more expressively happy to me, despite looking less like a smile.
Jam it back in, in the dark.