If Nokia buys into the Android platform, its stock price will go up. Why? Because it's perceived as a safe option and no one can argue with that.
Nokia has the Symbian-Qt-MeeGo strategy going on now, all looking great on (technical) paper but it's actually still a big question mark for most people outside;
especially after the last few boners Nokia has pulled out of its pants.
At the very least Nokia can play to its strengths (hardware) and ride Android's hype; it may even learn a thing or two by keeping their enemies close while Symbian and MeeGo are being simmered to perfection.