Okay, so you're probably thinking "Dude, 4E is stone cold dead. Why are you clogging your gaming shelves with it?" Well, I've only played the 4th edition of Dungeons & Dragons twice but I liked the design concepts. I was glad to see the designers were bold enough to stop polishing the same apple over and over and try something new. When the game was announced I pre-ordered the core books at my FLGS and was pleased with what arrived. Alas, 4E seems to have pretty much died before I could play it more fully somewhere--and few of my group seem enthusiastic about trying a campaign with it. Nevertheless, I have had several 4E books on my wish list to get in order to go a little deeper into the system and be ready in case I ever end up in a group which wants to play.
So I just recently bought three of the power books to add to the Arcane Power book I purchased earlier. The core books were good but obviously the options for characters were limited and I wanted to have these "power" expansions. If I ever run a game it will be the core books, the 2nd and 3rd player's handbooks, and these four power books as the basis. The only other 4E books left in my wishlist now are the Shadowfell and Secrets of the Elemental Chaos setting books.
As for my three new books I will say that the art (the first thing I go through a book for) ranges from good to great. The content is good stuff, although I thought that they had more paragon paths than anyone will ever use, and crazy amounts of feats.