http://www.newegg.com/Product/Product.asp?Item=N82E16819115005
so, $183 Core2 6300
and ..
http://www.newegg.com/Product/Product.asp?Item=N82E16813128017
for $116
so $299 mobo/cpu combo, nicely fast stock, and very overclockable.
Vs.
http://www.newegg.com/Product/Product.asp?Item=N82E16819103747
for $182 X2 4200+
and
http://www.newegg.com/Product/Product.asp?Item=N82E16813131022
for $97
so, $279 mobo/cpu combo, nicely fast stock, and very overclockable.
Personally, as much as I've had great experiences with AMD in the past, I can't recommend them right now for anything of this budget level and above. If you're not overclocking, the performance is fairly equal at this price point, but you have arguably an easier upgrade path with Core2 (fastest current processors, proven Kentsfield support, etc).
If you overclock, it's not even worth wasting brain-cycles thinking about.
AMD will be back, but if you're buying now, AMD is only for low end solutions logically. Personally, I still think many budget gamers are pretty well off getting a sub-$100 A64, a cheap NF4 DDR1 mobo, and the best video card they can budget in with the rest of their bucks.
For gaming on a budget, getting a $200 video card instead of integrated or a $100 one can easily double your experience, compared to a $200 cpu instead of a $100 one. Case in point :
$100ish A64 3700+ Single Core w/7900GS $200ish
vs
$180ish Core2 6300 Dual Core w/7600GS $110ish
Even though the C2 is much beefier, in almost all game situations that 7900GS is going to run circles around the 7600GS ..
Ok, enough rambling, build smart

Have fun!