[Psitticine]

I always use dates as part of version numbers. I'll start with 1.(date), like 1.070106 for something compiled today, and will go up to 2.x, 3.x, and so forth when there is something truly major changed in the beastie-in-question.

Actually, I start with 0.x, until I have something that actually works. 1.x is the stage where it is supposed to work but has a bunch of bugs, and 2.x is when I think I've gotten all the vile stuff out of it. If there's ever a call for a major rewrite or a ton of new stuff gets added (or, more commonly for me, the graphic assets are redone), the major version number will go up one.

It's not entirely traditional, but I've seen others do the same thing, and it works for me.