If you are looking for the not so mainstream book, go to Tsunami. It is located on busy Willamette, but their parking lot is somewhat adequate. I like how they have older books, so they are cheaper than buying brand new ones. They also do sell-back so you can exchanged ones you have read for new ones. Rare and out of print books are also generally available, or can be ordered. I'd definitely browse here before you go to the larger chains.