Here are some of my recommendations for traveling to Portland:
Powell's Bookstore (of course)
Chinese Tea Garden (get the jasmine pearl tea and the Chinese tea egg)
Nicholas Lebanese Restaurant (there are pictures of the original owner around the walls; he lived the American dream). They have bread that looks like inflatable pizza dough. Order the mezza platter with the Lebanese spinach pie.
OMNI science museum
Hollywood Theater
Take the street car and the max line. You can take the street car around the circumference of downtown which only takes one hour.
I also liked Marrakesh Moroccan restaurant. I liked the B'stilla Royale. It is also fun to watch the waitress pour the tea. (I just hope they get their carpets cleaned.)