I come from a .NET background and I've done a few simple things in Silverlight. I'd love to adopt that and make my site and games Silverlight only; but I hear it has a fairly low install base.
I know Flash has a much higher install base.
I also know that everyone seems to say that HTML5 is the way things should be heading; but there is still a bit of a bumpy road ahead.
Short of maintaining three code-bases; are there any cool tools that would allow me to write once and end up with three versions of the same game? I'm guessing the answer is 'No' but from a theoretical standpoint, I can't think of any reason why it wouldn't be possible.