For $2300, I would definitely go with Intel Core 2 Quad Q6600 Kentsfield, EVGA 8800GTX, and a 750W or above PSU. That would be around $1300 so you still have another $1000 for mobo, RAM etc.
Does your budget includes LCD panel? if yes, then go with Core2Duo E6600.
Newegg carries all those.