The second (and someone more important) thing is good Asian language support through GTK, something Trillian utterly lacks (and the older versions of Windows I use don't have decent Asian language support to begin with). In the process of getting GAIM configured, I decided to finally switch to GJiten (which, unfortunately, seems to be unstable as all hell, although I think we've come to mutual understanding, as I haven't crashed it recently) from the xjdic in kterm dictionary setup I was previously using. In the process I finally got around to getting kinput2 all configured (I had to, if I intended to enter kana without having xjdic handy to translate for me), which has mostly been good (it makes entering 日本語 text much easier, at the expense of catching a premature shift before a lot of my capital letters when I'm typing quickly. I'm thinking about changing the default key to something else instead of shift-space, as that is pretty bloody annoying now that I've put it into actual use. Plus I keep hitting ctrl-space by accident anyway -- I'm obviously an emacs user at heart. I'd just use ctrl-space, but unfortunately, that would screw up the mark in emacs).
I still need to get some sound issues worked out -- one major drawback of my GAIM installation is that the sounds simply don't work on it. Also, the volume control (namely under XMMS) also doesn't work. It looks like I may have to get sysadmin on the sound daemon/kernel driver's ass.
At any rate, between GAIM, OpenOffice, sound support under Linux, a CD burner on my Linux box (which I honestly haven't gotten around to configuring yet) and a number of other things, I'm slowly but surely making my Windows box superfluous, making it possible that at some point in the near future I'll be able to get rid of my Windows desktops altogether. And this has made solid progress towards my "Less is More" philosophy that I've been trying to adopt in the current transitional phase of my life.