If you like Macs you don't get a new computer, you get a new Mac. If you like Windows/Linux, you just get a new computer. It might be a Dell, a HP or a ThinkPad, you might have a preference, but in the end the specs matter much more than the brand.
If Nokia starts shipping Androids, they'll likely be the ThinkPads of smartphones. Rock-solid, reliable, great hardware, all boxes ticked, something of a following, but if you're in a pinch, there's an HTC that does the same for $100 less.
The only option for Nokia is figuring out how they can pivot their current smartphone market leadership into a niche that can compete with Android, the iPhone and BlackBerry.
I don't have the recipe, but it's going to require some very clear and bold leadership, that's for sure. Also, shipping three or four competing platforms isn't part of the solution, either (Symbian S60, Symbian 3rd gen, Maemo and MeeGo).
They actually have also S40, but that is for feature phones. I believe that they want to get rid of S40, put S60 on low end and MeeGo on high end phones.
But Symbian 3rd gen (aka. Symbian^3) is indeed different from S60 (which has 4 editions: 1, 2, 3 and 5), with 5th edition becoming Symbian^1. As a matter of fact, Symbian^4 (in which the current UI is replaced by the Nokia Qt SDK) is positioned for a 2011 launch according to http://en.wikipedia.org/wiki/Symbian_platform
It's the Qt SDK that I counted as a new platform in itself.
Long story short: Focus. Nokia can't have two promising and incompatible smartphone platforms.
I want a cellphone that's also a computer. I don't need a small computer, I don't care that it has a touch screen.
If they'd launched the 770 with a cellphone+3G modem (or GPRS at least, don't remember when it was launched), Android might not have existed today. They really dropped the ball there.
Nokia should take a page out of the HTC playbook: Implement Android but have it's own flavor through TouchFlo.
Remember, there are much more folks who want phone than those who want pocket computer or toy.