I chose Vargr as my favourite PC race - I like the idea of constantly trying to assert my authority over the other players, and encouraging do-or-die tactics - it's such a change from my real world persona.
When DMing, as baddies, I use the Sword Worlders (stuffy, anachronistic, easy-to-offend, militaristic racists) and I'd like to use the K'Kree (hmmm - for the same reasons!) except they're too far away.
The Zho are the 'big' baddies, as my campaign is set in 1100-1107. The players know that war is brewing, but not if I intend to follow canon, while the Characters have NO idea (well, they're starting to get an inkling) so all they know is that Imperium - Good, Zho = Bad.
I intend to cause them problems with that attitude 'real soon now'...
For real ultra-baddies though, you can't beat the Imperial Navy!