Turning on ClearType mode if you’re using an LCD monitor helps a lot in improving readability. Ubuntu, by default, doesn’t have ClearType turned on. However, you could achieve really nice font smoothing by just choosing an option in the settings.
In order to turn text smoothing on in Ubuntu, do the following:
* Go to System > Preferences > Appearance
* Go to the Fonts tab
* Under rendering, select Subpixel Smoothing (LCDs)