The following list contains an index of the major build and version numbers for a few Microsoft products. This list is primarily for the Office Server System (OSS) developer so it doesn't cover all Microsoft products. It's a work in progress… if you would like to contribute, please post to the comments of this article and include a citation where the version number can be validated.
Why create a list like this? Because I have needed it numerous times in the past and frankly I'm sick of having wade through my stack of books or the incredibly hard-to-find-things Microsoft knowledge base. Maybe it will help someone else, but it will now be easy for me to find from anywhere.
SQL Server (v7-present)
v 7 RTM
v 7 SP1
v 7 SP2
v 7 SP3
v 7 SP4
v 2000 RTM
v 2000 SP1
v 2000 SP2
v 2000 SP3/3a
v 2000 SP4
v 2005 SP1
v 2005 SP1 + KB918222
v 2005 SP2
Content Management Server (MCMS)
v 2001 RTM
v 2001 SP1
v 2001 SRP1*
v 2001 SRP2*
v 2002 RTM
v 2002 SP1
v 2002 SP1a
v 2002 SP2
SharePoint v2 (WSS v2 & SPS 2003)
WSS v2 RTM
WSS v2 SP1
WSS v2 SP1 + KB887981
WSS v2 SP2
WSS v2 post SP2 rollup (KB900929)
SPS 2003 RTM
SPS 2003 SP1
SPS 2003 SP2
SPS 2003 post SP2 rollup (KB897722)
**SharePoint v3 (WSS v3 & MOSS 2007) ****
WSS v3 & MOSS 2007 RTM
WSS v3 & MOSS 2007 SP1
WSS v3 & MOSS 2007 Infrastructure Updates
WSS v3 & MOSS 2007 August 2008 Cumulative Rollup
WSS v3 & MOSS 2007 October 2008 Cumulative Rollup
Be sure to check Spencer Harbar's killer Post SP1 page with links to all the hotfixes and version numbers… more than I have here.
* SRP = Security Rollup Package
** - SharePoint v3's architecture is such that MOSS is treated more or less like a feature pack, thus the underlying versions are the same between WSS v3 & MOSS 2007
[Updated 12/15/2005] Added WSS & SPS post-SP2 rollup updates.
[Updated 5/22/2006] Added SQL 2005 SP1 & post SP1 hotfix KB918222
[Updated 5/26/2006] Fixed CMS 2001 SRP1 & SRP2 & SP2 (there was no SP2 for CMS 2001, rather two SRP's for SP1). Thanks to Stefan for pointing this out.
[Updated 12/13/2008] Added all the major updates and security rollups for SharePoint v3.