I'd go with at least a Phenom II X4. The motherboards look ok, but if you want dual GPUs later, just verify it has SLI/CrossFire support (usually both). I'd personally go with an ASUS board.
There is no new AM3 motherboard that do SLI. There are a couple old nforce chipset ones, but I wouldnt recommend one for a new system.
If you want to do SLI or Crossfire, with those cards, I'd look at 750W PSUs. I have an i7 setup and 1 GTX 460, but am looking at getting another, which requires at least 750W.
A single 460 only requires a 550W PSU, a second one around a 650W (assuming you are getting good quality, newer designs). A 5570s can crossfire on a good 550W PSU.
I would take your first build, but replace the 5770 with a 460 (1GB) unless you strongly feel you will buy a second one as an upgrade in a couple years.