Question: What's your prefered method to name your software releases?
Like Microsoft: alpha - beta - final - service pack...
Like Google: gmail beta - beta - beta - beta - :)
Like some softwares: 0.2 - 0.3 - 0.9999...

Answer: 
We don't release alpha/beta software to our customers. Therefore we simply use:

* x.0 (for major releases, containing important/lots of new features)
* x.1, x.2, etc. (for minor releases containing minor new features and enhancements)
* x.y.1, x.y.2, etc. (for bugfixes/maintenance releases)

(where x,y = 1,2,...)
The way we have been naming our releases is typically Phase number. With most of our contracts being government projects we will roll out the first release and then will perform Phase 2, Phase 3, Phase 4 as the entity decides to move along with new feature requests (and acquires funding for said future developments).