Chophouse and Wynkoop are great suggestions ... there is also Dixon's, which never disappoints. (If you'll be eating breakfast in town, save Dixon's for breakfast, though.)
Here's a different idea: the Pepsi Center (sports arena) has a gorgeous restaurant inside called Blue Sky Grill. It is decorated like a Western ranch -- a very expensive one, that is.
"Log beams that make up the walls and parts of the ceiling were reclaimed from Yellowstone National Park fires. The rest of the wood ceiling is made of old snow fences. The floor is made of 100-year-old wood planks from historic barns. Stone columns and two grand fireplaces are made of Fremont Gold stone gathered from a quarry in Pueblo, Colo.
"The restaurant is decorated with Western art, antler chandeliers, wrought-iron lighting fixtures and antiques. Comfortable leather chairs surround the fireplaces, and the dining chairs are made of raw wood and leather."
The food is Western cuisine, as well: elk quesadillas, Rocky Mtn trout, pheasant, bison, and so on.
The entrance is on the south side of the arena, lower level. It's always open to the public on nights that there is a game (and with hockey and basketball, that's almost every night during ski season) ... other nights, too, but sometimes it's rented out (if there isn't a sports event). So you would need to call ahead, possibly.
Anyway, it's an idea, a little different ...