Touristy stuff? Have you been to Seattle before? There's the givens, like the Pike Place Market, Space Needle, SAM Sculpture Garden, Hiram M. Chittenden Locks, Golden Gardens, Alki Beach, Greenlake (I live nearby!), etc.
Downtown Seattle is not the happening place, by the way. The neighborhoods of Capitol Hill, Ballard and Fremont are really cool to walk around.
Would you be willing/able to leave the city? You should really think about visiting Mt. Rainier National Park if you'll have access to a car.
Hit up Feierabend for some awesome German beer and food:
http://www.feierabendseattle.com/Ivars on the waterfront is great for fish and chips, as is Spud down on Alki and in Greenlake. Gallerias in Capitol Hill is really good if you're up for some Nuevo-Mexican food.
Do you like music? Easy Street Records in Queen Anne (near the Space Needle) is awesome.
Do you like games? Pink Godzilla Games is a fun Japanese game store in the International District.
Give me some ideas of what kinds of food you like, and also how much you're willing to spend, and my wife and I will make some more recommendations.