I don't know all the correct terminology for this, but what I would like to see changed is for sounds (the typing animation, IM beeps, etc.) to still happen even when the client isn't the active window. I can't tell you how many times I've been checking email or working on a texture or whatever and missed people talking to me because I can't hear them. (And my monitor isn't big enough to tile the client & whatever other app I'm working in, and still be able to do anything in the other app, so please don't tell me to do that =)
#!