After reading the extensive hint How to work in OS X without using the Dock, I began to due just that, and I haven't looked back. I love working without the dock, but using Konfabulator only for new email notification was a little 'overkill.' I recently found The Unread, a freeware app to handle this simple task. It's just a menubar readout of your unread email count, nice and simple. Between that and QuickSilver, I never need the dock any more!
[robg adds: I do use the dock, but I still found this to be a handy little application -- it shows unread messages in any of your mailboxes that you care to count, as seen in the screenshot at left. So while the dock is telling me I have four unread messages, The Unread shows 60, and a quick click on its menubar icon shows the other 56 are on a few of the various mailing lists I read. Quite handy, and saves a trip to Mail to figure out what I do or don't have in my sub-mailboxes.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040418225236345