This software has two versions: Combo updater and Intel. They are both available for use.
For those of you concerned about time zones and daylight savings, the 10.4.5 update has got you covered for both 2006 and 2007. VPN connections to Cisco servers are also enhanced, especially when using NAT. Compatibility with third party applications and devices should improve as well. Finally, the update includes all previous standalone security patches.
If you want to learn more about what the update includes, head over to the Apple website where you'll find detailed information.