I've used the picoPSU-90 with that motherboard and the Intel Pentium G860. Maximum power draw for the whole system (DVD-RW, motherboard, G860, 8GB RAM, 500GB HDD) running Prime95 large FFTs was about 65W.
If you're using the integrated GPU of a SandyBridge processor and not adding a discrete GPU you're good to go, though not so sure when you get up to i7-2600K and the like. Celeron/Pentium/i3 no problem. i5/i7 probably no problem.
Don't bother with http://www.thermaltake.outervision.com/ for picoPSU / mini-ITX calculations it's off by a factor of 2. I have made my own measurements using a Kill-a-Watt and having built dozens of mini-ITX systems.