So I signed up for Windows Live Mail beta (the successor to Hotmail) a few weeks ago, and if I liked Outlook, I would really like it. It is certainly better than Yahoo! Mail (plain), and looks and acts like Outlook, you can right-click on a message and bring up a pop-up menu to forward, reply, reply, all to a message, just like Outlook or Outlook Express can. They also have a really good blog which does not appear to be as subject to the censors at Microsoft as Google's blog is subject to the censors at Google. Microsoft bloggers, in general, post pretty freely (while I'm sure they can't say totally negative things about the company, they do explain their rationale for why they do things. For example, on the Windows Live Mail blog, here, they post actual problems that they are having with the service and say when they plan to fix them. Google (Gmail), on the other hand, never says when they are having problems or what they plan to fix. I like Gmail otherwise (it is fast and efficient), but the fact that they never post when they are planning (or having) an outage annoys me. Yes, I know it's free, but I still think they should say something when they know it is broken (or going to be broken)
Windows Live Mail not as fast as Gmail is though. Plus, it only saves sent messages for thirty days. Gmail saves messages forever, which is much better.
I'm still waiting for an opportunity to try Yahoo! Mail beta, which I signed up for last fall. They sent me an email in December saying that I was on their list of people waiting to test it, and that I should be patient. I think I've been pretty patient by waiting three months.