[Mr. Flopnuts]

Restaurants:

Dick's (Seattle's equivalent of In n Out, it's not as good, but they are fantastic, and a Seattle staple)
Ivar's (Chowder)
Pagliacci's pizza
The Met (One of the best steak houses in the country. It's ****ing expensive as shit)
Thai Food is amazing there, as Bearcat said. I don't have a favorite in downtown, but it's hard to go wrong almost anywhere out there.

Those are off the top of my head, I'm sure I'll think of others. I always tell everyone to have an Alaskan Amber or 12 in my honor. It's my favorite beer on planet Earth. I'm not the connoisseur that Reaper is, but I love the stuff.

The Fremont Troll
The Soundgarden (yeah, that's where they got their name)
The EMP
Seattle Center as a whole can keep you pretty busy.
I think the Pacific Science Center is a blast. Check out the Pink Floyd "The Wall" laser show. Loved them when I was a raging stoner, but I'm sure a beer buzz would enhance the experience as well.
Pioneer Square for bar hopping, however Ballard has some killer Irish Pubs that are all within walking distance of each other.
The Big Wheel is cool from what I've heard, but I haven't been up there since they put it out.
The Underground tour is pretty cool.
Pike Place Market is a place you could burn a couple of hours.
Depending on who's playing, you should be able to catch a pretty good show at the Showbox. They have a very intimate venue, and it's a great experience.

Again, there's more. That's just off the top of my head. The place won't leave you bored, that's for sure.