Well the reason I say that is I found 3.0 GHz quad core P4 with 8MB cache on ebay for around $250.
Thank You all btw...
P4... as in Pentium 4 or AMD Phenom X4? Because there is no such thing as a quad-core Pentium 4.
Yes, Core 2 Duo will work in LGA 775 socket, but only with compatible motherboards. Same socket doesn't mean same support.
i3 will be better than the E5200.