I have three stores that I hit regularly. I will rate them for you.
3rd best is Prairie Arms (3809 Norwood Dr Unit 1, Littleton, CO, 303-346-7135). It is where I recieved my NRA (CCW) training. They favor Law Enforcement, but all are welcome. If they don't have it, they can get it.
2nd best is Shootin' Shop South (303-798-6792, 5827 S Rapp St., Littleton, CO 80120). It has a small shop feel. Whenever I am there I run into a few guys who hang out there even if they aren't buying anything. Dave and Scott are good guys and Scott is a very capable gunsmith. They aren't the cheapest in town, but they know my name when I walk throught the door. Customer service wins me over every time.
1st place goes to Green Mountain Guns (303-985-7240, 3355 S Yarrow St Ste 113, Lakewood, CO 80227). They are usually well stocked and they have good service. I was surprised that they have better prices than chain stores. I have purchased half of my collection from them. They clearly have lots of regular customers, because their consignment section is one of the best I have ever seen.
Heavy