This place is a minor Mecca to me. My younger sister and I orient ourselves by this tiny little city on a hill, and we plan her visits with me around time at Ikea. Think that's sad? You've obviously never been there.
I know all Ikeas are set up this way, so Pittsburgh's isn't special, but it is still magical. The place winds and curves through sample room after sample room. Each time you see a new one you actually think "hey... this could be MY house!" It allows you to dream and see things set up in a way that WILL inspire you... even if you then go get more expensive stuff at another retailer (although I never do).
The cafe makes for a great break in your visit between seeing the sample rooms, and then going downstairs to the textiles and home-wares, the kitchen tools and home lighting, the posters and plants... AAAAHHHHHH.. i want to go there right now.
(back to the cafe for a second... DEFINITELY eat there. It is cheap and tasty and will give you fuel for the coming trek through the wilderness of wonder that awaits you downstairs.)
After checking out I highly recommend grabbing frozen Swedish meatballs and a couple packs of sauce because building your new furniture will take a lot out of you.
Enjoy!