Basicly, post the music you use while role-playing. I'll start with mine first.
2033 Metro - Intro Song
http://www.youtube.com/watch?v=89YX7IztODk
Great for some passive RP, especially during sad passive RP.
Metro 2033 OST - Guitar Song
http://www.youtube.com/watch?v=2Rz2HvRMvEE&feature=related
Play this when sitting over a fire or in an abandoned area. It's even better if your character knows how to play the guitar ICly and you are at the moment.
Deus Ex: Human Revolution Menu Music
http://www.youtube.com/watch?v=ub1wpY4Xq6w
This is a great song for playing on a CCA character or anyone in the city. I love it for patrolling, attending CCA meetings, sad IC moments on my citizen, or even planning things out with my friends IC.
Creedance Clearwater Revival - Fortunate Son
http://www.youtube.com/watch?v=ec0XKhAHR5I
I don't usually listen to this type of music but it's an awsome song for sweeps on your CCA character, or event getting being a citizen in a sweep (fighting against the CCA units sweeping). Fun during an outlands events like mortar shellings and firefights with OTA.
If you have any songs, go ahead and post them. This is just my line-up.