If all you want to do is impress your Windows and Mac fanboy friends with eyecandy, then, yeah, install compiz. Show them twirly desktops, exploding windows, all that crap.
Linux is free, but you can contribute money to the distro of your choice. Windows is not free, and though you pay for it, you do not own it. You buy a license to use it in a very limited way. That's a better motive for using it than mere eyecandy.