In yet another sign of the times, Powell's Technical Bookstore is now closed. This happened last fall, I believe, but I just came across it when attending Code4Lib Northwest in Portland earlier this week.
There is a much-smaller (relative to the previous Technical Books) Powell's 2 location, with computer and science books. This store is on the same block as the large Powell's store.
I'm learning to love reading on my Kindle, but I'll miss the bricks-and-mortar stores, no doubt.