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: 
Major.Minor.Release.Build

While Release and Build increments should not contain "breaking changes" (for example have a different file format to store documents), i'm not absolutely sure if Minor releases are allowed to.

The meaning of the alpha, beta suffixes are for me:

Alpha/Preview: Hey, i got something that i want to show. 

Beta: The feature set is complete so far, but there are some bugs left.

Release Candidate: I think that there aren't any (major) bugs left.

Final: There could be still bugs, but i have to release at some point ;-).
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).