Favourite Diva: Whitney Houston (Janet close second)

Oldies:
Dusty Springfield
Dionne Warwick
Aretha Franklin
Stevie Wonder
Smokey Robinson
The Stylistics
Gladys

Weird Music (as in, music my brother deems weird of me to listen to) -- most of these artists have been featured on The O.C. but I was way cooler long before Mischa Barton thought she discovered them.
Rooney
Postal Service
Ben Jelen
Jet
Jem
The 88
Modest Mouse

Fluff:
Atomic Kitten
Gareth Gates
Delta Goodrem
Will Young

Others:
Jamie Cullum
Gavin DeGraw :love
Jason Mraz
John Mayer
Michael Buble
Amos Lee
Katie Melua
Jane Monheit
Seal
Patricia Kaas (fairly new)
Queen Latifah
Joss Stone
George Michael

These are just off the top of my head so, I'm sure I've missed a few.