Enable RGBA Transparency In Ubuntu 9.10 and 10.04
As you probably know, RGBA transparency was planned to be released with Ubuntu 10.04 LTS Lucid Lynx but it eventually didn't made it because of some issues such as various applications crashing and so on. RGBA transparency has been confirmed to be included in Ubuntu 10.10 Maverick Meerkat by Mark Shuttleworth at UDS-M but if you can't wait, you can try it using an Ubuntu PPA.
So why use RGBA transparency and not the transparency that comes with Compiz? Well, because RGBA doesn't make everything transparent the way Compiz does, but some elements such as the font and controls/buttons is still perfectly visible.