I like Adium's Mockie message style, but I like it more with a few things hidden. Just tossing this up here so I don't have to keep copying my changes around to new machines.
cd ~/Library/Application\ Support/Message\ Styles/
git clone git://github.com/fixlr/mockieminimal.adiummessagestyle.git \
MockieMinimal.AdiumMessageStyle
Pretty much just this:
# /Contents/Resources/styles/basestyle.css
81,82d80
<
< .topleft, .protocol, .sender { display: none; }