The entire UI is built with the GNOME shell-
Unity or GNOME 2, you mean.
For the upcoming 11.04 release-
11.04 is already out.
Compiz is a system which allows the user to interact with the desktop as if it is a cube or a multiple sided shape.
Well, that's one aspect of it. It's actually the effects' engine. Shadow, bluring windows, desktop cube, etc.
sudo aptitude install compizconfig-settings-manager
sudo apt-get install compizconfig-settings-manager
You can get the most recent version (Maverick Meerkat 10.10)
Natty Narwhal 11.04 actually.
Also, the beta 1.3 Wine packages seem to run better than the stable 1.2 packages.