They'll probably be packed after the marathon, but the aforementioned Track Town Pizza (on Franklin Street), Steelhead Brewery (5th Street), and the (three?) McMenamins' (High Street, 19th Street--right across from Prince Pückler's Ice Cream, and North Bank) are excellent choices. Villard Street Pub (15th and Villard) or The Oregon Electric Station (also on 5th Street) ain't bad either.
Hey, that's me! I run laps on Amazon and Rexius, and back and forth on Ridgeline, way too much. I'm considering making a map of everywhere I've run in Eugene, and then trying to fill it up...I get excited whenever I find a new trail to run on--even if it's 30 feet long and just attaches a cul-de-sac and a dead end.