Just a heads up to you guys. It's 121.3mb. I'm downloading it now.

Anyone know what new features it adds? 

I guess it would be good idea to check out MS official website and find out what features Vista SP1 offers.

I just did check Microsoft's site. Apparantly it adds no features, just makes it more secure, more reliable, and faster.

Well, those a three plusses for me.

more reliable meaning what? less breakdowns?

The main changes are:

- File copying no longer claims to take 10,000 years to complete
- DirectX 10.1 (requires an ATI Radeon 3000 series card; Nvidia doesn't support it.)
- Google Desktop Search now works with Vista
- Kernel version increased to same as Server 2008 (no new features though)
- Easier for administrators to lock down systems

There are practically no performance improvements according to several sources of benchmarks comparing an unpatched retail version and a fully patched SP1 one. Vista is still a lot slower than XP. See: http://www.anandtech.com/systems/showdoc.aspx?i=3233&p=6

Vista SP1 has been available for about a month now on microsoft.com; it is only now on WU.

XP SP3 is also due out soon, with performance improvements that will widen the gap between XP and Vista even further.

Well, I reccommend you not downloading this service pack, as I cannot get sound to work anymore. Great!

the SP also lowers performance of the OS

What sound card do you have? A friend of my has an X-Fi and his hasn't worked since the update, whereas mine works fine. Odd.

Mines just onboard sound which uses the AC'97 driver.