I don't use the dock much at all, so here's what I do to keep it out of the way. Open the Terminal and enter these commands (the part after the $):
$ defaults write com.apple.dock launchanim -bool no
$ defaults write com.apple.dock magnification -bool no
$ defaults write com.apple.dock autohide -bool yes
$ defaults write com.apple.dock orientation -string top
$ defaults write com.apple.dock pinning -string end
$ defaults write com.apple.dock tilesize -int 16
This hides the dock in the top right corner under the menu bar, with the nice side effect of freeing up the few pixels it eats even when hidden in the other three screen edges. The few times I need it, I usually just toggle the autohide setting via the keyboard (Command-Option-D by default; configure a better one in system preferences), though it's possible to hover the cursor just under the menu bar too.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040423170608616