The rumor mill today is producing an interesting news: Microsoft might be thinking of buying RIM. This is one of the million rumors that might not mean anything, but it is a good one...
Would it make sense? I believe so.
Microsoft is missing a HW play in mobile. They do not have a device. They are fighting against two vendors, Apple and Nokia, that have devices (and services, and operating systems, but so does Microsoft). It has been proven (so far, open source is changing this) that it is nearly impossible to deliver a great experience without controlling the full chain: from the device, to the operating system, to the service (and RIM has been phenomenal at device and service, not that much on the OS in my opinion).
Microsoft being a HW company? Yes, they do it already, with the Xbox. It is not that far from what they are doing.
Why not doing a device from scratch, then? Well, it takes two/three years (too much) and RIM is so cheap today that they would make money just buying the stock... The BlackBerry Storm looks like a spectacular device, even solving the issue of tactile feedback on a no-keyboard device. They have more coming. And they have a full grip on the high end of the enterprise market.
Imagine RIM+Microsoft together in the enterprise, when Nokia just abandoned it and Apple has no intention to get into it. It would be a near monopoly, excluding open source. It would be so much fun... David and Goliath... Nice thought for the weekend ;-)