Installing Ubuntu 8.04 (Hardy Heron) on a ThinkPad T61p
Display / Video
To enable 3D acceleration, the proprietary NVidia driver must be installed. To do this, I installed EnvyNG (envyng-gtk in Synaptic), then ran it (System Tools --> EnvyNG) and asked it to install the NVidia driver.
Unfortunately, there are some annoying bugs in the NVidia driver. The most annoying one is that after resuming from suspend, you will often get a blank white screen. To get past it, simply type in your password and press enter, and you will be returned to your desktop. This bug is documented in Launchpad  and a partial workaround is available .
Another problem is that the driver does not report the correct refresh rate to Compiz, resulting in rough animation. To fix this, install the compizconfig-settings-manager package, then go to System --> Preferences --> Advanced Desktop Effects Settings. Click on General Options, go to the Display Settings tab, uncheck the Detect Refresh rate box and drag the Refresh Rate slider to 60.
Finally, Compiz animations are also choppy due to NVidia's PowerMizer feature, which slows down the GPU to conserve power when it is not in use. This works well for 3D games which constantly use 3D acceleration, but poorly for Compiz which uses the GPU in small bursts. To solve this problem, I made a couple of shell scripts which keep the GPU at its highest speed while running on AC power.