Current reports indicate that how well the 45nm CPUs will overclock depends on the lot, so its a toss up. I think if you where to buy Intel for overclocking either pick a G0 Q6600 or wait for Intel's 45nm process to stabilize. Just make sure you use applications that can make use of more than 2 cores. Otherwise a fast dualcore is probably a better buy anyway.
The Phenom 9600 has been clocked to 3,25 GHz with air cooling. From what several german forums say, all the new Phenom's (9600 BE) are able to reach 2,8-3,0 pretty easy now instead of at launch where they didn't even reach 2,6 GHz... and with the B3 stepping launching today, which seems to be able to get overclocked a little higher, the Phenom is definitly not a bad choice even for high-end gamers now.