Graphical user interfaces (GUIs) may not be necessary for personal computing, but they sure have made it much more accessible and easy. You can get an idea of how the GUI has evolved over the past decades here, Windows Evolution. From 1.0 to Vista. Maybe you think Vista Aero is pretty cool. If not, you can get an idea of Microsoft’s concept for the future here, MSNBC: Microsoft unveils table top computer.
You can see beaucoup demos of Compiz on Youtube, but you should really check out this side-by-side demo of Vista vs Compiz to get an idea of which one really rocks. And remember, you have to get Windows Vista Home Premium, Business, or Ultimate to get Aero.
Here’s a quickie how-to from OS Novice, "How to Install Compiz Fusion", that should be enough to get started. I haven’t yet tried it yet myself, and suspect that it takes a bit more tweaking under the hood than I’m prepared to do right now. But I will point to any additional tutorials/how-to’s I find as time goes on. Eventually, I expect Compiz will be added to mainstream Linux distributions, so the tweaking won’t be necessary.