Right now would be a great time to upgrade ubuntu, most of the bugs have been fixed in the previous release and their is plenty of new driver support.
Press Alt+F2 and type in "update-manager -d" (without the quotes) into the command box. Update Manager should open up and tell you: New distribution release '8.10' is available. Click Upgrade and follow the on-screen instructions.
If you have a separate home partition and dont mind reinstalling the os, download the iso, reboot and install with jfs.
I have noticed a dramatic speed increase formatting the partition to jfs, jfs definately boots much faster and accesses files/programs quicker for me.
I got tired of ext3 a year ago, switched over to reiserfs, and that was super fast, jfs is even faster and way more stable.
Download the Intrepid Ibex beta iso from here