I'll buy the books, and like all other editions, will mine the good stuff, dump the bad stuff, and houserule the gaps. What excites me more about 4e than previous editions did is at the inception, it SEEMS like it's going to require less house ruling because it's more in line with my group's working definition of high fantasy.
Of course, I kinda thought the same of 3e before I actually started reading it. Even then I was enthusiastic with most of the changes--I just didn't feel it went nearly far enough. Finally killing off Vancian magic is the tipping point. Speculation runs the gamut on this forum regarding that issue, and frankly it's the litmus test for 4e's success in my mind: can they kill Vance's shadow fully and offer a solid alternative? I want to believe they can.