Bridgetown Hobbies and Games is located at 3350 N.E. Sandy Blvd, Portland. They have a webpage: http://bthobbies.com/. I'd say that's got about the most extensive collection of minis, paints, books, and other accessories in Portland. About 15 block further east on Sandy is Things from Another World, which is mostly comics and collectable toys, but they also have D&D books and they used to have some minis (Games Workshop, Confrontation, some wargods long ago..), but I haven't been since their last GW sale sometime last year.
in SE portland there's Guardian Games. It's tucked behind the office depot on Martin Luther King Blvd and about Stark. The address is 315 SE 3rd Ave., Portland. They don't have a webpage but they do have a myspace page: http://www.myspace.com/guardiangames. It's a big space, and they've got a huge screen with a projector for video games, as well as some computers and alot of tables. I know they have regular magic tournaments, alot of magic cards and D&D minis, they also buy/sell singles. They also had some old used books as well as the new stuff. Not much by way of minis, but friendly and good about special orders.
Out on the west side there are a couple of game stores. Rainy Day Games is in Aloha (past Beaverton), at 18105 SW Tualatin Valley Hwy, Aloha. They also have a webpage http://www.rainy-day-games.com. It's been a while since I was there, but I think they have alot of books and board games, and a fairly good selection of minis.
Ancient Wonders is in Tualatin, and fairly close to the I-5 highway. The address is 19060 SW Boones Ferry Rd, Tualatin. They also have a webpage! http://www.awonders.com/. It's been over a year since I've gone there, but my recollection is that they do magic tournaments on the weekend, and it was always rather dark there. They did have quite a few very old miniatures, like clan wars, and they had a pretty good array of books.
Wizards Toy Chest used to have books, some terrain stuff, D&D singles, and collectable card stuff. I haven't been there in probably 2 years, but I've seen the sign from the highway that implies it is still there. However, they don't have a working website anymore, so I'd only go there if it was on the way somewhere else.. 
There's a Hobbytown in Clackamas across from the Clackamas town center in the Promenade, a few doors down from the Target. They had some books, alot of reaper minis, and various collectable minis (wizkids, heroes, d&d), but it's been a while since I popped in there. Also had model cars and woodland scenics stuff, paints and brushes..
Lastly, it's a bit out of the way, especially if you're going by bus, but Zgames in Vancouver is a great place to game. They have at least 4-6 tables for tabletop gaming at any given time, and very nice set-ups for them as well (unless it's a tournament day). They are a friendly bunch - they have comics, board games, puzzles, gaming books, the best selection of confrontation minis in the area, alot of games workshop minis, and a fairly good array of the collectable minis. I think there are various trading card game boosters behind the counter but I don't pay much attention. They also carry the full vallejo paint line, privateer press paints, and the GW foundation paints.. can't recall if they have the other GW paints, but I don't think so. Their address is 2100 SE 164th Ave Suite D111, Vancouver. Their webpage is www.zgamesonline.com.
Lastly, there's a good bunch of NW gamers located at http://www.ordofanaticus.com/modules.php?name=Forums. They do alot of matchup for gaming there, and sub-rent space from a historical wargaming club for gaming on tuesdays, thursdays.. possibly sundays. They don't chat as much about RPGing, but I know at least some of them do, so if you're looking for a gaming group of whatever flavor, it's a good place to start looking. There's a mailing list of portland area gamers on yahoo, too, but I can't remember the name.. pdxgamers? Someone at Ordo might be able to tell you..
Happy Gaming! And enjoy the nice weather while it lasts..
/ali
ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHyou86dZKCZnZp6tMDOq5ysZZmjerG70a2jmqaUYryzepBycHJvZGQ%3D