I guess this is a good deal. Bing is at least as good as Yahoo search, if not better. If MS had bought yahoo last year, they may not have released bing at all. Now they can merge the strengths of both bing and yahoo search, and hopefully come up with a strong contender to G. Overall this is good for users.

EDIT: it is also better than last year's failed deal because Yahoo can still stay alive, instead of being swallowed by MS completely.