Whoops, I spoke too soon. I'd uploaded a slighty-out-of-date version of the dock icon. The new one is pending approval, so don't go updating your Adium quite yet. Sorry about that. (This be old news...)
A recent email from HunterTV prompted me to update the reddit alien dock icon I'd made a while back for Adium -- the greatest IM client in the world, ever.
There aren't any major changes, but the IM notification animation is more dramatic (look how excited the alien is!) and there's now a jolly speech bubble behind the alien when it's just chillin'.