P35 will take the Penryn Quad's easily. You have an easy upgrade path, just pop in a Quad Core CPU when you actually need it. Once more games and programs take advantage of more than 2 cores, you will get at least twice the performance by just a simply drop in CPU upgrade. The Q9550 runs about $300 these days and can be clocked at 3.6Ghz easily on air. Some people have them at 4Ghz and these things might drop to sub $200 at some point... That would more than double performance in apps with 4 or more threads.
Penryn is about 10% faster clock for clock, core for core faster than Conroe, but it may be a larger performance gap as time goes on and SSE3 is utilized more. So you can cound on 10% more performance just by switching to Penryn clock for clock, and you can count on 50-99% more performance by moving from 2 to 4 cores applications with more than 4 threads and then you can probably overclock it higher in general, to say 3.6Ghz, or even 4Ghz assuming you grabbed a Q9650 later when they are EOL and bargain price.
So best case scenario
Q9650 @ 4Ghz (4.4Ghz Kentsfield Equiv)
2 to 4 cores, 75% (avg) increase in multithreaded apps
I dunno, seems great to me... Heck, I might even upgrade my Q6600 to a Q9650 if they fall around 200 bucks and skip Nehalem as it would require a new waterblock, a new motherboard and new memory... Who knows what else too.
