Not trying to copy Justin's What do you eat while playing, but this is what I listen to:

One of my fav. songs.
1. Plain White T'S - Our Time Now
2. Sean Kingston - Fire Burning
3. Kid Kudi - Day and Night
4. Taylor Swift - You Belong With me... ()
5. AFI - Miss Murder
6. Micheal Jackson - Billy Jean, Beat it
7. Blink 182 - I miss you

THOSE SONGS ROCK!!!!! unk:unk:unk:unk:unk:unk:unk:

Lets see-

KT Tunstall- Suddenly I See
I'll have to think of more.

I listen to in game music approximately 100% of the time but sometimes I'll listen to my own music that's not in the game like:

The Offspring - Your Gonna Go Far, Kid
Queen - Bohemian Rhapsody
KT Tunstall - Suddenly I See
KT Tunstall - Black Horse & The Cherry Tree
Kelly Clarkson - Already Gone***
Kelly Clarkson - My Life Would Suck Without You***
Avril Lavigne - Complicated
Lights - Saviour
Lights - Drive My Soul
Lights - The Listening
Sonata Arctica - Flag In The Ground
Sonata Arctica - Paid In Full
Green Day - 21 Guns
Tokio Hotel - Automatisch
Rammestein - Ich Will
Nightwish - Nemo
Within Temptation - Angels
AFI - Prelude 12/21
Evanescence - My Immortal

And there's TONS more that I can't think of at the moment right now.