In addition, if you choose Start, Default Programs, Associate a file type or protocol with a specific program, you'll see a new entry in the protocol section, called Search. Use this screen to configure what program opens when you click on a file that uses the Windows Search protocol.
For details about changes SP1 makes to search, see this Microsoft Knowledge Base article.
For more information about the Windows Search protocol, see this separate Knowledge Base article.
Microsoft has made some smaller cosmetic changes to Vista as well in SP1. The Disk Defragmenter (Control Panel, System & Maintenance, Defragment your hard drive) now lets you choose which volumes to defragment.
In addition, if you use BitLocker for encryption, you can also choose which drives to encrypt.
Vista SP1 aims at performance and stability improvements, including faster browsing of network shares. On our test machine, however, the beta unaccountably won't allow us to browse to another Vista PC on the network. We can browse XP machines with no problem, but not to another Vista PC. Odder still is that we can make a remote desktop connection to take over the other Vista PC using remote control, but can't browse the PC using Windows Explorer or the Network Map.
On our test machine, installation of SP1 went smoothly, if slowly; it took about an hour and fifteen minutes on a 1.83GHz Core Duo laptop. The machine rebooted several times, and did so automatically, requiring no intervention after installation began.
The bottom line on SP1? Considering that it's still early beta, it's tough to know how much of a performance improvement it will offers users when it's released early in 2008. The only significant interface change is to the search function, and that change will affect you only if you decide to use a search technology other than Windows' built-in search.