The Search menu option is no longer on the Start menu, and when you kick off a search from the Search box on the Start menu, the text at the bottom of the results has changed (from “See all results” to “Search Everywhere”). [Update: There’s also a new Pause button on the Indexing Options dialog box, which allows you to suspend indexing for 15 minutes.]

The Remote Desktop client has a redesigned user interface.

The disk defragmenter command allows you to specify a volume to defrag.

There’s a new version number in the About box. SP1 uses the same kernel and has the same version number as the newly released Windows Server 2008.

If you have a copy of Windows that was activated using the Grace Timer or OEM Bios exploits, you’ll be asked to activate, presumably within three days. If you can’t supply a valid product key and activate online or over the phone, you’ll be unable to continue using Windows Vista.

If you have a system that fails a WGA validation check, you’ll see a black background instead of your regular desktop wallpaper. You’ll also see some messages warning you that your copy of Windows Vista is “not genuine.” You will lose no functionality.