Gmail

I've been using Google's new web-based email service, Gmail for a few months now. I like it enough that it's replaced Hotmail as my personal email. My 2 favorite things about Gmail:

1. It groups back & forth email conversations. What could be a dozen emails is just one in Gmail: Gmail screenshot.
2. Gmail has the same the minimalist, down-to-business style of interface that Google has. I hardly even notice the ads unlike Hotmail with it's giant banners: Gmail screenshot.

You can't just sign-up for Gmail. Google calls it "beta" which means it's still in testing. During this testing you need to be invited by an existing user to get in. If you want to try out Gmail let me know and I'll send you an invite next time I get some more.