rnbeatz, Take a look at the Apple site for the new specs.
http://www.apple.com/powermac/architecture.html
The new system ahs improved more architecture than just faster CPU:
Faster RAM from 133 to 400 mHz. PCs have been running this stuff for a while (about 8 months I think). Proven and stable.
Bigger FSB. Faster thru-put to the rest of the systems.
Apple has caught up or surpassed the PCs in every feature except CPU speed. But they are giving you 2, so that is moot.
Go with the newest system, you'll have a more relevant machine for longer.