I use Azureus because it is the pwn. One of two Java programs I use. (Guess the other?)
Yeah, I use Azureus regardless of platform. I'm not sure how it compares to some of the other ones (I have used μTorrent, but I didn't find a reason to use it over Azureus), but it does everything I need.
The only other Java program that I use regularly is Zend Studio. I've been using vim over it for a while, but that's probably because I haven't had any large-scale PHP projects in a while.