Well here's my two cents, since i'm in the same boat, except i know what i'm getting to some point.
I'm getting the Q6600 to play games on, but i'm also getting it to deal with all the threads my pc runs, including the anti-everything that wants to run all the time. It will fit me, since i'm somewhat of a mega-tasker. I don't know what your budget is (probably didn't read it) but mine should be around 1500, maybe more, but i'll explain later.
I plan on getting the Asus P5K Deluxe since i'm going to overclock the FSB from 1066 to 2000, and i'm not sure if i should get the DDR3 board because i have to wait for DDR3 chips to launch and see how expensive they are. Otherwise i've got a nice pair of G.Skill DDR2-800 that i've seen get overclocked to 1100 - So it's either 1:1 with the DDR2, or it's extreme bandwidth with DDR3.
Anyway, that should leave the Q6600 somewhere around 3.5ghz but i also plan on getting a nice 300$ watercooling set to cool that, the NB/SB, and maybe a 2900XT that i'll overclock too. I might also add in an extra two radiators on my loop. And this doesn't quite matter but i'll be getting probably a 750w modular PSU.
The only problem is that this board can only have 1 gfx card running on 16x. The X38 boards have up to 2 16x lanes and an extra 8x lane, or one board i think had 4 8x lanes. Anyway, you could either look into my build which will only be good for single card graphics, or wait for X38 like i might be and find out which board takes the Q6600 as high as the P5K Deluxe. (Because i want to XFire my board, i have a 21" CRT, so max res for me).
As far as longevity, i know you'll understand this because you're on a single core +3200. I'm running an Athlon XP +3000 @ 2.1ghz, and it's run all my games pretty well for the graphics cards i've had in this box, it's just multitasking that it sucks at. And i've been on dual-cores... I don't find them all too special, and since they've been around for quite some time now, quad-cores are the chips to keep you into the future for a while before intel releases it's hyperthreaded chips (i'm so excited for that).
Anyway, my point is, i've had this athlon for a good two years (i bought this cause it was cheaper, even when the 939 socket was fairly mature) and it's ran me fine. You can only think that a quad-core at this point would last me many many more years - and since i/we are overclocking everything, my box should last me a good 4 years or more till i need to replace the gfx card, and then maybe 7 years before i buy a new box.
Should you go for my build, you'll have a high-end rig for quite some time, even with the release of new chips. Unless intel makes the new arch over 1.5x better clock for clock, nothing is going to really compete with a quad-core in terms of overall performance. What could touch a 3.5ghz quad except a better quad? And even if intel is making native quads, as well as AMD, they're reducing cache, and to really drive my argument home, how can you say no to a quad-core that costs you $266? So a new one comes out, low-end dual-cores were freaking $266 just a short while ago. Pair a Q6600 with a P35 board and you have a free overclock from 1066 to 1333 (i.e. no voltage increases on anything. Just ramp the fsb!)
Hope this helps.
EDIT: I'll be running 2x1GB dual channel, but if i was willing to tolerate Vista64 driver issues i'd go for 4GB+ for sure. But i'm not.
EDIT2: The next quads will be running at 1333FSB stock and have 6MB of cache, so you can't buy those if you want to overclock. It's the 1066FSB quads you want to buy (they have 8MB of cache too).