GAIM's dependancies suck ass.
XMMS is the best damn music player I've see yet.
X based Email clients suck ass. But then, I was using Calypso on Win and that's one tough act to follow.
GIMP is teh roxor.
Just one more year or so of development and Linux distros will reach the point where they will be ready for "prime time". It's frustrating, in a way, using it and seeing how close it is, but knowing that it's not at the point yet where you can recommend it to your co-workers.