Ubuntu Linux is not the prettiest of operating systems. I mean sure, it has some nice neat themes, but when it comes to toolbars, windows and other graphical stuff, it really does not cut the cheese.
Along comes Beryl, no, not a 60 year old grandmother from Wagga Wagga, but a program that sits on top of linux that makes it pretty. Beryl (and XGL windows manager) takes not all that long to set up, about 10 min, as long as you have the correct video drivers installed, and as soon as you restart, you have the most pretty and cool operating system around.