Honestly, all of those specs might be a little tough for < $700.
I purchased a Dell Studio 15 (1535) from the Dell Outlet a few moths back and it's all I use now. I've been able to play CS:S, TF2, L4D, and even COD4 on it.
Specs: T5750 (2.0Ghz C2D), 3GB DDR2, 250GB 5400rpm, DVD+-R/W, 15"...