Seattle is much like Portland, but goes to bed later. Portland was a bit sleepy - great town, but sleepy.

Seattle has
- tons of bike shops, many with rooted fixie culture. lots for diy-ers
- hills, sometimes long and steep, and ways around them if you're tired
- tons of bike routes, generally well thought out
- lots of folks on bikes
- great food
- beer. mmmm... beer
- good music
- smart, progressive people
- mountains nearby
- water all around (bonus - it's blue)
- temperate weather (ride all year, on and off road)
- beautiful springtime
- no state income tax

and so on...

I lived in Austin and Portland before Seattle. All three are great, but Seattle is the best for riding around town, and for many other things - not bbq,blues,or mexican though :'(