Let's assume you are in Denver. Plenty of fast food joints to choose from, but the best seems to be Biker Jim's Gourmet Dogs and if you don't mind vegetarian, Mad Greens is excellent. It will benefit your health too! In Colorada Springs there's a great place, Bourbon Brothers Smokehouse and Grill. There's also a vegan place for fast food which is highly rated: Santana's Vegan Grill, but the huge wadge of fries is pretty unhealthy.
Marigold Cafe and Bakery runs the gamut when it comes to a good fast food restaurant: everything from escargot to fish and chips makes an appearance on the menu. You could go Italian with a pizza or veal scallopini, or you could go French with salmon roulade, without going wrong. Plus, there’s that crucial “bakery” component.
All the desserts are made on site and get constant “Best of Colorado Springs” notices. There are lemon and lime tarts, there’s tiramisu, there’s creme brulee, and there’s a near endless variety of cakes. Essentially, there’s something sweet enough, rich enough, or tart enough for any palate.