The version number is entirely up to you. Do what makes sense to you and be consistent. Nobody says you have to start from 0, or 0.0, or 1.0, or 1.1.
Great programmers have actually used the version numbering system as local jokes. Examples (Wikipedia):
Since version 3, TeX has used an
idiosyncratic version numbering
system, where updates have been
indicated by adding an extra digit at
the end of the decimal, so that the
version number asymptotically
approaches π. This is a reflection of
the fact that TeX is now very stable,
and only minor updates are
anticipated. The current version of
TeX is 3.1415926; it was last updated
in March 2008
For METAFONT:
Metafont has a versioning system
similar to that of TeX, where the
number asymptotically approaches e
with each revision.
Finally, not quite a version number, but equally interesting, is that Google's initial public offering (IPO) was filed with the SEC for raising $2,718,281,828 (notice that e~2.718 281 828).
My point is: don't feel that you need to follow the crowd. Be creative and consistent.
