Windows Vista SP2 is on it's way to RTM according to the Windows Vista Team Blog. Some of the key benefits of SP2 are:
You can read the rest of the announcement here.
Although off the shelf PCs may start shipping with SP2 quite soon, other end users will have to wait a little longer in Q2 before it is available to download.Windows Search 4.0 for faster and improved relevancy in searches
Bluetooth 2.1 Feature Pack supporting the most recent specification for Bluetooth Technology
Ability to record data on to Blu-Ray media natively in Windows Vista
Adds Windows Connect Now (WCN) to simplify Wi-Fi Configuration
Windows Vista SP2 enables the exFAT file system to support UTC timestamps, which allows correct file synchronization across time zones.
You can read the rest of the announcement here.