I went with the dual core Atom board here:
NCIX.com - Buy Intel BOXD945GCLF2 MINI-ITX DDR2 945GC Dual Core Atom 1PCI Motherboard Retail - BOXD945GCLF2 In Canada.
Don't expect to game on it, but it's great for web surfing, and even HD content (1080p can be a bit sluggish, 720p is great). I'm powering mine with a 90w picopsu, and it works fine thus far. The only drawback, IMO, is that you need a separate bracket for spdif (though it does have the motherboard header) and there's no DVI connection; it's vga only.