Here's my post from the recent purchases thread for riding 100 mi/week. I already had some essentials, so this isn't a complete list of everything you'll need.

Purchases since July:
Shimano 105 SPD SL pedals
Kool Kovers cleat covers (came in handy when I had to walk my bike a mile)
Fizik 3mm bar tape (love this tape)
Conti GP 4 seasons 700x35 tires
Topeak D2 digital tire pressure gauge (very useful)
Craft Performance bike short (very good, fits snug so returned a med for large)
Specialized EMT multi tool
Smartwool light cycling socks
Giro LX leather half finger gloves
Kask k50 helmet
Tifosi Jet sunglasses
Craft leg warmers

Purchases coming soon:
Kinetic trainer
Arm warmers