I don't wanna get to technical but you should have at least 2 gb per core (on vist anyway) so thats 4gb if you run duo 8gb if you run quad. Besides, the quad isn't a true quad anyway...it's just two duo's slapped together on the same core.
huh?? Where did you get that info? 2gb is enough, 4 is better, but not needed and 8 is overkill (unless you are into CAD or heavy GFX programs/dvd decoding etc.)
To the OP, The best price vs. performance CPU right now is a Q6600. they can be had for just over $200, are quad core and can OC to 3.2-3.6. Not too much slower than an E8xxx and you get 2 more cores.
edit: The E8xxx's are good and just fine for gaming, but personally, I like to OC the heck out of a CPU and the voltage issues they have influenced my choice.