Gmail at Five Years
I hope everyone on the face of the earth has a Google email account by now. If you are still using Yahoo email just because you have been for ten years go ahead and make that switch. The sooner you do it the easier it will be to make the transition. Gmail is worth it just for their superior spam filtering software. I found an interview with Gmail's Senior Product Manager (what does that mean?) that's informative. Another reason to try Gmail is that it's always evolving. There's always something new to play with on it but it never changes so much to where you feel like you have to re-learn how to do the basic stuff. Gmail: It's Fun!
For further reading I found a history of Gmail written up at Wired.com. Thanks to the mighty Lifehacker for the link.