Seattle is a cool place to live, I have relatives up there. The summers are definitely better. But the winters, I don't know your feelings on sunshine, because it vanishes. There is a constant and depressing cloud cover. My people live in Bellevue, which ideal IMO. I liken it to Sugarland, without the commute.
Congrats! It's coming up on my 2 year anniversary since I started working at Microsoft. I'm based in Houston though, working as a Premier Field Engineer (SharePoint). What team are you going to be on? I got to spend 2 weeks up in Redmond when I first joined. I loved it up there and would definitely consider moving if I decided to join a new team. Let me know if you have any questions, as the new employee stuff is still somewhat fresh in my mind .