IKEA is an experience. You have to drive way the hell out to Tukwila, generally battling traffic at least one way, and then you get to battle the crowds in the store. But it is oh, so worth it. IKEA has it all. Tables, chairs, beds, hooks, utensils, dishware, etc. And it's all very reasonable. Their lighting section is great, and they have a gorgeous room of rugs. I love the room mock-ups so you can dream (and drool) about what you could do to your place if only you had the space/time/energy/money.
Here are my suggestions: Go on a weekday/weeknight, eat first (their cafe is scary to me) and make sure to take your Paxil first. On weekdays the crowds are much more manageable, and maybe after they finish their renovation (complete with wider aisles) crowds will be less of an issue. Shopping on a full stomach will prevent you from thinking that IKEA hot dogs are a good idea (they never are), and if you take your Paxil beforehand, the long lines won't give you an axiety attack.