Recommended Reading! In roughly chronological order.

[meowminx]

Chuck Dixon
The Catfile
(90's era goodness)

Darwyn Cooke
Batman: Ego & Other Stories
(Includes 'Selina's Big Score', which is awesome)

Ed Brubaker
Vol 1: The Dark End of the Street

Vol 2: Crooked Little Town
(out of print?)
Vol 3: Relentless
(If you read one Catwoman trade, read this one.)
Vol 4: Wild Ride

Nine Lives of a Feline Fatale
(Out of print? Collection with stories from all eras.)

Tim Sale/Jeph Loeb
Catwoman: When in Rome
(Not part of regular continuity, but still a great read)

Paul Dini
Heart of Hush