Mac OS 10.6 Is Way Faster Than 10.5

My iMac's hard disk failed. It was under AppleCare warranty, so the service personnel replaced it. Previously, Mac OS 10.5 was on the old HDD. The new HDD came with 10.6 installed. Upgrade! Though, it's a bother because the system back up worked on 10.5, but does not fully work on 10.6. So, I'm having to replace some apps, and reinstall stuff, and reconfigure stuff.

In case you were wondering: Mac OS 10.6 is significantly faster than 10.5! I guess there was a bright side to my HDD failure.