You're close to everything, including buses that will get you to some of the really good restaurants. Given that you have 5 days, you'll probably want to vary some cheap and some nice meals. In downtown, there are the Tom Douglas restaurants that we are all obligated to mention and the Pike Place Market, which has a couple excellent options for sit down and dozens of stall to snack from during the day. While you are here, do visit the market.
If you take the bus tunnel to the International District, there are a lot of good inexpensive restaurants to choose between and a good amount of geeky stuff (if you've got a little otaku in your geeky mix). King Noodle is very good. Kau Kau BBQ is good. Ping's Dumpling House is good, but mainly when he has the special juicy pork dumplings (Sunday only?). Uwajimaya has a decent food court. There are also more refined options down there that stand out: Tsukushinbo and Maneki would be my top picks.
You can also hop on the number 11 or 49 and head to Capitol Hill. There are TONS of restaurants up here at all price points. Skillet Diner. Spinasse (although this is more of a higher end romantic restaurant). Cafe Presse. Rancho Bravo Tacos (cheap!). Marination Station. Mamoon (within walking distance of your hotel/the convention center).
If you can let us know what you like and don't like, we can narrow it down quite a bit. :)