Doom 3 runs on Linux. As do other id Software titles, such as the Quake series.
Also, there is speculation that the upcoming new version of Trillian, named
Astra, will run on OSX and Linux as well. The developers have said that they got their core engine to compile for both platforms, and hinted that it might be released for more than just Windows. No official announcement as far as I've seen, however. I haven't used Linux as a desktop in a few months, so I'm not sure of the state of IM on the platform. On my Powerbook, I use
Adium, which is based on the gAIM engine, and of course, use Trillian on the Windows PC.
If you're looking for "programmer's" text editor, have you tried
Eclipse? As for emacs and vim, the "ancient monstrosity" description may fit emacs, which is on version 21.4 and has been in nearly constant development since at least the 1970s. But vim is a much newer "clone" of the older vi. Once you get used to vim, it is a very powerful editor, absolutely perfect for editing config files.