Windows 7/2008R2 Service Pack 1 has been officially released to MSDN and volume license, if you have access to these go get it!

For Windows 7, mostly catch-up of all released and unreleased bugfixes.
For Server 2008R2, the same plus Hyper-V support for dynamic memory and RemoteFX.

Build is 7601.17514.101119-1850

(note, if you recently "acquired" a leaked copy from something called "WZOR" you are good to go, it matches the official release) :D

Yeah, got it through my technet and volume license yesterday. Gonna test the hyper-v changes on the sandbox before going live with them. :)