Through the generosity of a friend-of-a-friend, I finally got a Gmail account (cantoni AT gmail.com). So far I've been pretty impressed, especially with its ability to group mail messages by threads. I pointed a couple mailing lists I follow to my Gmail account just to generate some traffic. I was pleasantly surprised to see how well it combines replies together in a threaded fashion. It's a good combination of digest most with the benefit of seeing each message individually.
More exploring to come. I wish it had import/export features — import so you could play around with more “real” data and export so I don't get locked in.