I'm looking at a similar situation myself. I'm going to build a new Intel system very soon. I wanted to wait for January and the Penryn non-extreme release, but my current rig is killing me.
I decided to go the cheapo CPU route myself looking at the 2180 or a 6550 on a Maximus Formula board, 2G RAM, and a 2900 Pro flashed to XT mode. This will leave me plenty of room for upgrades til Nehalem/AMD's newer offerings. I figured I would OC the hell out of one of the new 1333 FSB chips and run dual core til January. Then drop in a Penryn, an additional 2900 pro for CrossFire, 2 more gig of RAM, and Vista 64.
By January, I should have a good/great DX10 gaming system that should do it's job for a couple years.
I would have loved to use the newly reviewed 8800 GTs in SLI, but the X38 chipset doesn't support SLI apparently. If anyone has successfully ran any of the G80s on an X38 in SLI, please let me know!!