Well... I just so happen to live here in the rainy city of Seattle so let me fill you in on a few things.
Cap Hill: The "gay/alternative" area. Most of the gay bars are here (though not all as previously mentioned). There is also a Silver Cloud Hotel on the hill which is pretty decent and close to everything the hill and downtown has to offer.
Downtown: All your usual attractions: restaurants, movie theaters, acting theaters, the opera, the symphony, art museum and lots of shopping! Check out the area around Westlake Center if you want to shop. You can also catch the Monorail from Westlake center to the Space Needle, EMP (Music Museum) and the Pacific Science Center)
Belltown: Mostly residential, but close to the space needle.
Pioneer Square: Lots of the "straight" bars are in this area. It is close to both stadiums and usually attracts the sports crowds on game days.
Waterfront: Stretches almost the whole length of the western end of downtown from the North end of Belltown to the South end of Pioneer Square. Lots of "tourist" things to do but mostly small shops and restaurants. The Seattle Aquarium is here on pier 59. This is where all the cruise ships dock and you can also take the "Clipper" to Victoria BC. Oh yea, this is where the Pike's Market is too!
Eastlake/University District: As the name implies, this is where UW is. Lots of college kids and, again, shopping and dining. University Village is home to Seattle's Apple store, if you wanna check it out.
Queen Anne: A cool neighborhood on the hill across from Cap Hill. Lots of shops, restaurants and big homes. This is a pricey area, but fun to visit. Check out Kerry Park for a killer view of the space needle and downtown.
Ballard/Northgate/Etc: Residential neighborhoods of seattle but each with its own cool stuff. Check out Golden Gardens Park if you can, its a beachfront park and very cool. The locks in Ballard are also cool to see if you havent seen them before. Northgate is home to Americas first indoor shopping mall. It's not the best mall, but it is the first in the country to be called a mall.
Wallingford: Changes: Kind of a neighborhood bar just to the west of the University District.
R-Place: 3 floors of music/videos, dancing, etc. Decent place with a younger crowd.
CCAttles: Oldest gay bar in the city, serves the strongest drinks for the cheapest price. Nice people and a good vibe. No dancing, but the do have a pool table. Gets packed early but clears out early too.
Cuff Complex: Huge with an outdoor area. Probably the biggest melting pot of gays in the city. Dancefloors, several bars, lots of things to see. All in all a good place if you dont know where else to go!
Pony: Newest edition to the hill. Small, but popular.
Purr: Lounge style bar with sofas and comfortable areas to lounge in.
Garage: Not totally a gay bar, but a fun place. Has a bowling alley inside, pool tables, etc. Very fun.
Madison Pub: Your typical gay sports bar. Jukebox music, pool tables and darts.
Eagle: Your typical Eagle. Every city has one, right?
We have lots of hotels in Seattle. You can stay at the W or the Holiday Inn. We have it all. Look for a boutique hotel if you have money to burn. The Silver Cloud on Cap Hill is close to most stuff so is the Crowne Plaza. Just look up hotels in Seattle online and you will see plenty to choose from.
Other Things to See:
Space Needle: You have to see it, and go up inside. Its a Seattle staple.
EMP: Experience Music Project museum, right next to the space needle.
Asian Art Museum: In Volunteer Park on Cap Hill it is cool to check out.
Pikes Market: One of the must sees.
Aquarium: It's ok, but if you have seen one you have seen them all.
Monorail: Fun to ride.
Snoqualmie Falls: Beautiful
Woodland Park Zoo: A fun place for a lazy afternoon
I hope you have a great trip man! Let me know if you need anything else.