well looking around it seems i was mistaken and some i865g boards do support conroe though Intel's info on the chipset didn't say so.
an e6600 would easily eclipse an Athlon 64@2.4GHz and even one at 2.6GHz. have a look around at prices if you're interested. i wouldn't say i'm the foremost forum expert on Core 2 on the forum so hopefully someone else will post