I would have to take a look at the rules, consult the group I was with, and see what we wanted to do as a group. I would likely buy the books, but I hope that there would be significant improvements in 4E. (I know several people have expressed concern on these boards with magic systems, multiclassing, and other issues.)
Of course,t here are probably many different factors to consider. In another thread, there is a mention that Amazon.com has a mention of a Players Handbook II in May, 2006. This might mean that WotC is not releasing a new edition next year.
I would prefer a wait for a few more years on a new edition. I think that one of the selling points of 3.0 for me was the fact that the developers considered the input of gamers, including playtesters and people who filled out surveys. I would hope that WotC would at least try to understand why customers would want to buy a new edition, and not just economic issues. I think that it is possible that there is talk of a new edition at WotC. Then again, for all I know, WotC or the D&D line might be sold in the next few months -- which would impact our speculation.
I would hope that 4E would have something like the current D20 license. Possibly, a new edition might use some of the good ideas generated by other companies. (This could be a trade off between WotC and the other D20 publishers. There are many good ideas out there, so I don't see why WotC might not want to consider using them. There are already parallels to this -- racial substitution levels, racial levls, and action points have parallels in other products. Hero points in Arcana Unearthed do have seveal similarities with action points.)
Mind you, I think 3.0 was necessary. By the end of 2nd edition, people could play AD&D with very different rules sets (kits, the Skills and Powers books). Also, there were so many supplements that it was physically impossible to carry them all.