That's right, it's time for a technologically controversial post. :)
Compiz is the ultimate in eyecandy. Seriously. With wobbly windows; various window-switching mechanisms such as shift-switcher, ring-swither, and regular tab-switcher; a multi-desktop cube; Mac Expose-style effects; some wicked screensavers; and a whole array of window opening, closing, minimizing, focus/unfocus, etc animations, it clearly outshines Vista and OS X combined. It's also pretty darn efficient - as I type this, Compiz is using no more than 12MB of memory, and I rarely reboot my machine. :D
However, as cool as it is, I find myself using very, very few of the available plugins in my daily workflow. With my current setup, I have all three window switchers; a four-desktop cube; wobbly windows; open/close "glide", minimize/unminimize "genie", and focus/unfocus "fade" animations; current-desktop and all-desktop Expose effect; show desktop; and the spinning cube screensaver enabled. Of all these functions, though, I only use the cube regularly. I have it setup so that Alt+Ctrl+Left/Right arrow spins the cube, and I use that for switching between desktops. For switching between windows? I use Avant Window Navigator. With an icon for each window, I just click on the one I need to go to. And, of course, the animations, screensaver, and wobbly windows are ever-present and fairly unobtrusive. I just find that the majority of the available effects aren't useful in my everyday workflow. I mean, fish inside my cube? Drawing on my screen with fire? Not only not useful, but a nonproductive use of resources. :)
I suppose the purpose of having so many effects, other than sheer amount of eyecandy, is choice. However, choice or not, a lot of the effects are just plain useless, such as the aforementioned Aquarium plugin.
What plugins do you use on a daily basis, if any? And which plugins do you have enabled that merely gather dust? :)