I'm in the same boat. I generally avoid bleeding edge stuff because of the cost. I believe it's better to replace a system twice as often rather than pay twice as much. Of course it depends somewhat on your application.
I'm considering either a relatively low-end AMD X2 (3800+ or 4200+) or Core 2 Duo E6300 processor. You can get either CPU for $150-$200. http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2802
The question is which mobo to get.
the cheapest one with the features you want, that gets good reviews and overclocks the best... ;)