I've had good luck using Gmail. It's fast, fairly simple, and is available anywhere I have an internet connection. Also, I switched over to using it for my work and school email (using Gmail's POP3 access feature and some forwarding) probably about a year ago and it's worked well - I access all my email accounts from one place.
I saw a really helpful feature today that, while it may not be that new or even original, saved me from making an embarrassing common mistake.
I'm assuming that it guessed this by my message hint, but I could be wrong. Either way, it made me put on a geeky smile.