Salt Grass Steakhouse is great, although not in many areas (a few just opened up in Colorado).

I've been to Outback a few times, but I've never been too impressed with it.

A great "local" option is The Mint Steakhouse in Silverthorne, CO. All-you-can-eat prime rib for about $30, which really hits the spot after a day of skiing. If you don't want prime rib, you pick out a steak from the meat display and cook it yourself on their grills. In addition, they also have a "Locals Day" special a few days after most of the ski resorts close. Almost any cut of steak is about $8. You have to show up about an hour before they open to guarantee a seat.

The other "slightly upscale" option in Denver is Aurora Summit Steakhouse in Aurora, CO. Wonderful steaks topped with sizzling melted butter for about 1/2 the price of Ruth's Chris.