This out-of-the-way beer and burger restaurant has simply the best hamburgers in the Portland area, period.  Immediately adjacent to the campus of Pacific University in Forest Grove, I was told about Cornerstone by my perpetually hungry engineer buddies from work.  You don't go here for the ambiance...  It's small and doesn't have the glitziest interior.  It's a college pub, after all!  With only seven tables, there's not a bunch of seating either, but if you're looking for an outstanding alternative to the stock burgers served at other, more well-known places, this is place for you.  The service is super and the food comes to the table hot and fresh.
Pros:  Food, huge selection of beers, super service
Cons:  Not much seating, ambiance got lost in the Sixties
                        
more