CS5 - User friendly? Forget that, we're just gonna make the interface over complex, unintuitive, obstuctive, totally broken and completely un-stable! Hurp-durp. (Seriously, AVIOD THIS AT ALL COST)
CS5 has AMAZING new features though, for me that I do photo manip from time to time, the new content-aware saves me A LOT of time. And the new rendering options to make it easier on hair is great too, and then the new noise remover works wonders.