Whenever I went up there, I always went to the Depot for dinner and was never disappointed by the steaks. Pricier than the average spot but not out of control (good Maytag Bleu Cheese 10-oz. sirloin with sides for 27.95).
http://www.depotmissoula.com/menu
It's been nearly 10 years since I've been to town so I may have to look around to refresh my memory of other places to go. For those looking for a cold beverage, the Rhino doesn't disappoint. Somewhere between 50-100 beers on tap and a huge selection of scotches and what not. And for anyone who enjoys craft beer, and I know there are some on this board, Western breweries blow their East-Coast brethren out of the water. Sorry. Fact.
Looking forward to just getting into town and exploring next week.