The taxes you are concerned about would seem to take place, regardless of when you buy; they will not affect the actual transaction, but the operations of the business after January 2011. Thus, the question would not seem to be that of timing, but whether you should buy at all, given your level of anxiety.
The only reason to wait, would seem to be whether the prices of businesses will be lower, after the new taxes take place. But after that point, even if the prices come down, so will your ability to afford any purchase, because as you say, the proposed tax hikes will affect everyone - not just small businesses. So, it would seem there will be a leveling action across the board.
But I would not ask this question here; I would go directly to an accountant who does not have a vested interest in buying or selling a business, such as the writers of entries in this bulletin board. One of the questions you might ask is how your purchase of a business might even offer you an advantage, in buying a business. For example, if you finance such a purchase, will the interest on the loan be able to be deducted against the taxes that are proposed? That could turn to an advantage for you. But there is always another side: If that is the case, a lot of people will want to buy after January, meaning that the demand for business purchases could be high, and the prices will remain at current levels, or even go higher, as a result of the added demand.
You can analyze some things to death. Some people are "always getting ready to get ready", and never actually accomplish anything. If you are serious, narrow your level of questioning, aggressively and directly approach your research and then act decisively, one way or another.