Windows Live Mail Beta
I have to say that my off and on usage of hotmail over the years has probably jaded me toward Microsoft's web mail offerings. I was very skeptical of how good Windows Live mail could be. I was stunned. The only downside is that it isn't yet compatible with Firefox and Safari. This is a big downside for me, but they say that it is coming when you log in using one of the competing browsers.
The first thing I noticed was how clean everything was. There is little to no clutter. The interface looks very much like Outlook 2003. Their calendar looks a lot like iCal, and iCal looks a lot like the Outlook calendar. It would appear that their calendar sharing is pretty cool, but I didn't have much of a chance to use that. Everything is integrated at a high level. One of the coolest things was that when a mail came in while I was logged in, it just popped up at the top of the screen with no refresh or other fanfare.
The mail application has the spam filters and protections one would expect. It allows you to create folders, then use drag-and-drop to put your mail items into the folders. One of the coolest things about it is that you can move, delete, forward, or reply to any message by right clicking on it. They also are giving up 2 GB of storage for mail items.
I didn't look too deeply into it, but I didn't see any export items. If it were to support the vCal format for calendar items and offer RSS feeds for mail it would be hands down the best web mail client. Its a beta, so who knows how far they will go.
So far I am very impressed. I would have to say that it currently outclasses gmail pretty heavily, except that it doesn't seem to have an RSS feed. I think that as Microsoft increases how many users it has on Live mail, Google will have to respond with their integrated calendar and better contact lists.