Planning to upgrade soon (next month really) and thinking C2D is the way to go, but am intrigued by the promise of cheap quad-cores in the not too distant future...

Will an e4300 hold it's ground with an 8800GTS and 2Gb pc6400 cas5? I get the feeling I should either get a 4300 now with a view to definitely going quad-core or I should get an e6600 now and keep it longer? Some overclocking is fine but it might be going in a mATX case so temperatures are all-important (which is another reasons quad core is scary!) :)

Also I gather the e4300 might not like Vista as much as the e6600 ... something to do with virtualisation?

thoughts on e4300 vs. e6600 in games? Would I even notice the faster cpu?

Depends on your motherboard and cooling tbh. The two allowing you should be able to run it 24/7 at about 3.5/3.6 GHz. Although I would say at this point it is worth spending a little extra and getting an E6400. I dont know what the current lot are like but a recent batch clocked like mad

I have a E4300 and a 8800GTS and it works flawless on every game i chuck at it, although i have overclocked the E4300 to 3.3ghz.

I get 999FSP in Warsow and 200fps on average in CS:Source with everything on full.