Not going to happen. If Microsoft does buy Adobe, it will mark the beginning of the end of Bill's empire, because it means an idiot is in charge of corporate takeovers, and so this can only be the first of many stupid moves.

Adobe is a firm that caters to the media, the idea that Microsoft would go after Adobe just because of Flash irresponsible and demonstrates a lack of understanding about what Adobe does.

What is far more plausible, are talks about Microsoft buying the Flash division off Adobe (but still unlikely) or probably just talk of getting Flash on WP7, or getting Adobe to officially sanction a Silverlight-to-SWF (or Flash to Silverlight) programme.