Updated with the latest information.
As promised, Microsoft today officially released Service Pack 1 for Windows 7 (all editions) and Windows Server 2008 R2. You can find it at the Microsoft Download Center.
If you only have one or two PCs to upgrade, I advise waiting until the installer shows up on Windows Update later today. I’ve just completed the installation on a test system here; it went very quickly.
The Microsoft Download Center requires validation; after you pass that check, you’ll have the option to choose from multiple versions of the Service Pack code. The ISO file (7601.17514.101119-1850_Update_Sp_Wave1-GRMSP1.1_DVD.iso, 1953.3MB) is for IT pros who want access to all three SP1 installers in a format that can be burned to DVD. Most users will also want to ignore the four symbol files, which are for use with debug versions of Windows.
You can download separate installers for 32-bit and 64-bit Windows 7 versions
- 64-bit: windows6.1-KB976932-X64.exe, 903.2MB
- 32-bit: windows6.1-KB976932-X86.exe, 537.8MB
The Windows Update package should download automatically overnight. If you want to force it to download and install now, open Windows Update and select the check box next to the Service Pack 1 entry, click OK, and then click Install Updates.
If you’re getting Windows Update errors, try using the online fix-it tools available from Microsoft. Details in this ZDNet post.
Ed Bott (@ wordpress.com) 
I’ve been running SP1 since it appeared on TechNet, and I’ve gotta admit, it does fix some pretty annoying bugs that somewhat stained the Windows 7 experience.
Personally, I’m really happy about the incorporation of this fix for example, as that was terribly annoying.
http://support.microsoft.com/kb/975777
Once you’ve used it for some time, it is noticable that really the most annoying tiny things are now fixed, and it really does improve the experience of Windows, even though for the client-side, there are just hotfixes, RDP 7.1 and new HyperV tools (incl RemoteFX support) in it. Most of the notable changes listed refer to previously released hotfixes.
For Hyper-V, I believe this is a very essential service pack. I mean, who rolls out a VDI on a virtualization solution without dynamic memory when that improves VDI density by about 40% ?
But not only that, WS 2008 R2 had few more nasty bugs. I skimmed over the hotfixes list once it was released, and it appears that Microsoft did have now the chance to test Windows in actual deployments and fix issues that come up with it.
And seriously, issues such as http://support.microsoft.com/kb/975535 are highly critical. To actually incorporate that, you’re supposed to jack around with DISM and god knows what. Having it on the actual media is a much more viable solution.
Of course, Windows 7 is by no means a perfect OS, but with service pack 1 it does improve a lot. On both, the SOHO and enterprise markets. Seems a SP doesn’t always have to make substantial changes to the OS to actually improve it a lot.
I’m really looking forward to the IE9 release now, updating IE to a program that incorporates the Windows 7 spirit and API is really something that needed to be done and also was done now.
On a side note, I’ve been running IE9 RC without compatibility lists and automatic compatibility modes for a week or so now; and the amount of websites that can cope with it sharply increased. When the beta was still current, I also tried this and it resulted in many websites being broken due to legacy IE7 fixes, but nowadays, it does look better to me.
Success. I had to allow Windows Update to download a boatload of updates and things (me being a Luddite) before the SP1 item even showed up. Then, it was a half hour long task for the download and install. Three re-boots later, the job was finished. Afterward I used Disk Cleanup to get rid of the service pack backup (600mb large)
SP1 is now on board and everything seems to be running well.
“Of course, Windows 7 is by no means a perfect OS”
Why even go there? Pursuing perfection is a fool’s game.
The Microsoft Download Center requires validation !!!
Works just fine with RemoveWAT.
“Works just fine with RemoveWAT.”
Works just fine with a legit key, too.
“Why even go there? Pursuing perfection is a fool’s game.”
What I meant to say is that the SP1 does really elevate the Windows 7 experience to a new level with the few critical bugs that affect every intial release fixed.
Allowed windows update to handle the download & install of SP1, All went well without a hitch. Unless you have a need to download the x86 & x64 SP1 installers separately or the humongous 1.9GB ISO file windows update will work just fine for most users.
@ChrisTX Good point the fix you mentioned (kb/975777) in your post was most welcome. Now for the task of creating a Windows 7 + SP1 ISO.
What has to be done to pose a question that nobody else seems able to answer.