linux can offer great customisation, from different kinds of DE to different types of menus and themes, you can also get many kind of widgets like screenlets. there's also many distros to choose from depending on what you want.
i just started using Archlinux, and i'm liking it so far, you have to use the CLI a bit, but thats not necceserrily bad, you get to know more about linux and learn to do things sometimes faster, and after installing yaourt you can download most packages you may want, there are many up-to-date emulators, among them dolphin, pcsx, mupen64+. all in all it's a good distro if you like to customize, but not so much for new users, ubuntu or linux mint would be best to start with.
Compiz Fusion looks really awesome in YouTube videos, but when you use it, you'll realize that in terms of practicality Aero is better. I mean, what kind of "effect" is it that you can draw flames on your desktop by holding down 2 keys and using the mouse?
It's really unprofessional.
compiz-fusion has many gimmicky and useful features, i for one like to have a choice. currently i use a burn effect when i close windows and transporter effect when i minimize windows, useful? not particulary but i like the effects, also the 3d cube is useful for me, it gives me easy access to more desktops where i can have a browser in one and for example a movie or a document in another.