The Oregon History Center is well worth visiting. Also, "PAM" (Portland Art Museum) is among the better "major city" art museums.
I've been impressed with the restaurant at the Heathman, especially in terms of appetizers/salads. Higgins is also very good. In the Sellwood area, Caprial's Bistro is very well known. I think the food is on par with other restaurants in the price range. Perhaps one expects a bit more from a "celeb chef," but its easy to set the expectations too high.