Not sure of what food or vibe you're looking for but:
Jake's Crawfish- not the biggest fan of this place tbh but you'll find local seafood cooked pretty uniquely Portland and a pretty quintessential restaurant if its your first time there. Its right by the Ace too.
http://menus.mccormickandschmicks.com/JKCR/JKCR-Dinner.pdf
Tasty and Alder is also very close and is very good.
http://www.tastynalder.com/dinner/
I'm a fan of Higgins restaurant as well which is also walkable. Very Northwest focused food and its better than Jake's. Just not as historic.
http://higginsportland.com/nc-cms/content/upload/house_menus.pdf
If you want more of a scene with pan asian food, go to Departure at the Nines hotel. Rooftop restaurant.
http://departureportland.com/menus/
Little Bird Bistro is a good french bistro. They have a good burger.
http://littlebirdbistro.com/menus/Little Bird Dinner Menu.pdf
Cheap steaks and strippers: The Acropolis (far from downtown though).