Should Microsoft buy OnLive ?
There's no question a cloud gaming platform would very much complement Windows gaming and could be bundled similar to XBOX centre on every PC, tablet, phone etc. Not to mention it can augment XBOX itself. I am sure there are lots of people who would be satisfied with streaming a game to their XBOX and others who would prefer full game downloads/physical media, it would just complement XBOX as a complete entertainment hub. Once read that OnLive founder initially built the business up hoping Microsoft would buy it, it even has a cool metro interface with live video tiles.
Then again I may not know it but Ms could likely already have something like this in the works and buying unneeded infrastructure, small customer base and relatively shy brand-name may just not be needed and they already have some X-BOX branded game streaming service in the works.