I have an Atom 330 ITX board coming today that I'm pairing with a GTS450 for Folding and HTPC purposes... perhaps I'll have to replace it fairly quickly Both boards look awesome. $150 is a bit steep for me (Could just pop a H55N-USB3 + i3 540 in for ~$190), but I'm sure I'll find one for less somewhere. I like MSI's heatsink solution the most, I think.
4 PCIE lanes shouldn't be a detriment for my purposes, either.
That ASUS board looks like a little power house. Passive cooling means it'll be almost silent. Could also throw in a cheap AMD gfx card for some light gaming too.