This is all extremely helpful input. Thanks again! Some final questions on all this:
At this point I am, thanks to the input here, considering 3 CPU options.
1) E2180 for $80. 2GHz, 800MHz FSB, 1M L2 Cache
2) E4500 for $125. 2.2GHz, 800MHz FSB, 2M L2 Cache
3) E6650 for $180. 2.33GHz...