I actually don't use a pressed powder, so this won't really be helpful if you are absolutely set on that. But, in my opinion, the best powder is BareMinerals mineral veil (not tinted, not hydrating, just the original). It really blends concealor and everything underneath, and gives the skin a beautiful flawless finish.
100% Pure Cosmetics has pressed powders - the shades are limited though. they use a TON of organic ingredients, no petro chemicals, no synthetic fragrance, no chemical preservatives, etc. I have liked their brand so far (I own quite a few items from their line).