I didn't know anything about Seattle's trans community until this year's Trans Pride event, which was spectacular. The people are fantastic, caring, supportive, and fun!
There are a lot of fun places in and around Capitol Hill, some night life in other neighborhoods, and plenty of decent restaurants (it just takes some hunting to discover your personal favorites!)
I grew up in the north end of Seattle, which is kind of a boring part of town, but lots of small businesses to support and excellent parks.
It rains a lot (but not as much as portrayed in movies and television) and almost nobody uses umbrellas. When the weather is nice, the views of the mountain ranges are picturesque and lovely.
Most people in the neighborhoods I've lived in aren't particularly close with neighbors, but circles of friends and communities are very close-knit.
Driving in Seattle can be extremely frustrating, as the freeways and highways are not designed to handle the amount of traffic that the city's population creates (and all the one-way streets downtown can be tricky, and parking is expensive). The city is supposed to be quite bike friendly but I find the bike lanes terrifying. It's relatively easy to get around on the bus system, though - sadly, they are cutting service due to budget issues, but they have also done a lot to expand the areas covered, so there's a give and take around that.
The Seattle population is predominantly White in most neighborhoods, with varying pockets of different ethnic and cultural communities. The lack of melting-pot in the city can be frustrating at times, especially for people of color moving to the city. On the bright side, the place where Seattle's diversity does come out is in all of the family-owned restaurants around town. There is a lot of variety in what is available to eat (I'd say especially around the University District).
Sorry, lots of random information. I wasn't sure what you were looking for and got a little carried away, heh.