I use gmail for my main email account, and I use hotmail for anything that's bound to get a lot of spam/junk mail along with it. I prefer gmail because I like the thread/conversation system of organizing, the labels are easy to use, and it has a great search feature. Also, gmail has added a ton of additional features, such as pop3 access, forwarding, etc. so it's really easy to manage it from pretty much any client, if you like to use things other than web access to read mail.