Docks aren't for everyone. I use them to launch my favourite applications
with one click as opposed to the menu which takes more clicks and time to
search. They also work like the Windows 7 panel showing your open
applications. There are several good choices, but I like AWN the best with
Cairo being a close second. I can use the same bar in both KDE and GNOME
which saves even more time since the menus are structured differently. I
have a big monitor so that helps. On my netbook I have a timy one that hides
away.

GNOME Shell and Unity do not work well with a Dock, at least not for me
because it is more confusing than anything. Also Compiz features are wasted
in GNOME Shell and Unity which will be disappointing for many. I think that
it is going to have to grow on people because it is unlike anything that
most people have used, certainly in Linux and Windows. I am not sure about
the Mac because Shuttleworth is patterning Ubuntu after OS/X or so most
observers think.