SEATTLE is a moderately beautiful US city set in amazingly beautiful countryside, so a car or motorbike will give you ample opportunities to get out and explore the region. Try driving round the Olympic Peninsulas just west of the city -- real backwoods/ logging country. Very dramatic mountains. If you're a music fan make your trip long enough to include Aberdeen, hometown of Kurt Cobain (it's suitably bleak and desolate!)... In the city, there's a lot of live music in the evenings. Pike Place Market is not quite as great as the hype suggests, but worth looking at. I've never been to the Experience Music Project but have heard very good reports. On the other hand, going up the Space Needle is well worth it. Also: ttry to get to the top of the elderly Smith Tower in the downtown business district - though this may be closed to the public now). This site has a decent review of all the attractions:
http://seattlepi.nwsource.com/visitorsguide/