I've been having a lot of fun making a custom soundtrack for this game. The last game in which I had a custom soundtrack was Rallisport Challenge for the XboX. My current playlist inludes:

DJ Krush

DJ Spooky

Jerry McCain (blues)

Sinead O' Connor

DJ Soul Slinger

Big Black

Judas Priest

M.I.A.

Run Lola Run Soundtrack

The Minutemen

Dr. Octagon

Mobb Deep

The Roots

and

Ennio Morricone

What would be on your playlist?