Hmm... What?
No, not really. Wargamey, anime-feeling crap has slowed my purchases. If anything, a true announcement of 4E would probably accellerate my purchases. My group saw the rumors last week and said, "3.5 is good, we're staying put." That means I'd pick up even some of the marginal products (MM4, ToB) and most of the Eberron stuff. Then, I'd consider my library stable and move on with life.
In a way, I'm kinda hoping for 4E so that I have that solid cut-off point. Of course, if 4E really (and I mean really) rocks, then the cycle will start all over again.