If quiet instrumental material is what you are looking for, I have all the songs in my head plus I use sheet music so that I have a suitably wide selection.

For the vocal sets I play material from the following artists:

Don McClean 
Travis 
Queen 
Elvis Presley 
Steve Harley and Cockney Rebel 
David Bowie 
Robert Palmer 
New Order 
Credence Clearwater Revival 
Then Jericho 
Blancmange 
Depeche Mode 
Gary Numan 
David Gray 
Rod Stewart 
The Foundations 
The Beatles 
The Searchers 
The Everly Brothers 
Van Morrison 
Jeff Beck 
U2 
Maroon 5 
J Geils Band 
Semisonic 
Starsailor 
Bryan Ferry 
The Mavericks 
Dire Straits 
DJ Otzi 
Norman Greenbaum 
The Merseybeats 
Keane 
ZZ Top 
REM 
Duran Duran 
The Cult 
Anastasia 
Norah Jones 
Andreas Johnson 
Bryan Adams 
Muse 
Savage Garden 
Pink Floyd 
Elton John 
The Proclaimers 
The Pet Shop Boys 
The Monkees 
The Commitments 
Coldplay 
Ian Dury And The Blockheads 
UB40 
Jeff Wayne (War Of The Worlds) 
Sky (Toccata) 
Emerson, Lake and Palmer 
B Bumble And The Stingers 
Chris Rea 
Oasis 
Radiohead 
Sting 
Hootie And The Blowfish 
Morrissey 
Bon Jovi 
Blues Brothers 
Pulp 
James 
Status Quo 

The Rasmus 
Nickelback
Snow Patrol
Embrace