I own tonnes of them :O I have a whole drawer in my room full of them XD
On CD:
Alien Ant Farm - Smooth Criminal
Avril Lavigne - He Wasn't
Band Aid 2000
Bedlight For Blue Eyes - Waste My Time
Biffy Clyro - Mountains
Bowling for Soup - High School Never Ends
BFMV - Hearts Burst into Fire
BFMV - Waking the Demon
Cardigans - Love Fool
Cavalera Conspiracy - Sanctuary
Chemical Brothers - Galvanize
Children of Bodom - Blooddrunk
Clawfinger - The Price We Pay/Life Will Kill You/Prisoners EP
Dinosaur Jr - Crumble
FOB - This Ain't a Scene...
HIM (all of the singles from before Dark Light - [The Singles Boxset])
KIGH - Easy Tiger
MSI - Never Wanted to Dance
MSI - Never Wanted to Dance Vol2
Nightwish - Amaranth
No Doubt - Hey Baby
Offspring - Pretty Fly for a White Guy
Outkast - Ms Jackson
Panic! - That Green Gentlemen (3" disk)
Paramore - Misery Business
Richard X vs Liberty X - Ain't Nobody
Saosin - Voices
Scooter - Nessaja
Trivium - Becoming the Dragon
Velvet Revolver - She Builds Quick Machines
Within Temptation - Angels
Within Temptation - The Howling
*inhales*
On Vinyl:
Biffy Clyro - Who's Got a Match? (number 1210)
Children of Bodom - Blooddrunk (limited red vinyl)
FFAF - Waterfront Dance Club
Gallows - Staring at the Rude Bois
Go:Audio - The Woodchuck EP (number 68)
Innerpartysystem - Don't Stop EP
Panic! - 9 in the Afternoon
Also, I have the vinyl-CD combo Deathcar single