Here's about 10 minutes of brain dump that could become its own guide with lot more care and attention.
- Hotel Boulderado: it's right downtown, and walking distance to just about everything
- Quality Inn & Suites, still downtown-ish.
- St. Julien, if you're feeling fancy.
Otherwise, rent a car, and be sad that you have to commute in such a small town.
You shouldn't need to rent a car, just about anything is reachable in downtown Boulder by a short walk. Anything else, the bus system is great, and on-time. To get from DIA, take the AB bus to the Boulder transit center. It leaves every hour.
- Snooze (get here early, before 8:30), opens at 7
- Lucille's - cajun food, done real nice. Buttermilk biscuits, beignets, and collard greens are great. Get either the chicory coffee or the spice tea. Open at 7 (or before?)
- Brasserie 1010 has a good breakfast. French.
- The Kitchen - has brunch, but only on weekends. Best croissants in town, though.
If you have a car:
- The Walnut Cafe - open early, it's the local diner-style breakfast place (but the food's way better)
- Cafe Aion - like The Kitchen, but with more of a Mediterranean bent.
- Cured - it's a charcuterie, so their sandwiches tend to be an excellent baguette, a delicious cured meat, cheese, and a spread (or just butter). Get a coffee at Boxcar while you're there.
- Zoe Ma Ma - chinese street food. Very good.
- Frasca Caffe - really good panini, and if you're early, get a pastry, too.
- The Kitchen Next Door - neighbor to the more upscale The Kitchen, it's good food served quickly.
- Boulder Bowls - beans & rice cart, in front of the old courthouse on the walking mall. My go-to.
- The Mountain Sun - good pub food and great beer on tap. Cash only, but the ATM in the back only costs $1.
Along with the lunch places, these tend toward farm-to-table "New American" style.
- Oak - my favorite restaurant and the best bar in town too. $$$
- The Kitchen - $$$
- The Kitchen Upstairs - more of a bar / lounge than restaurant, but their half-chicken is amazing. $$$
- Brasserie 1010 - $$$
- Various sushi places. Zanmai's next to the Boulderado. Sushi Tora's good, then Japango, and Kasa too.
- Pizzeria Locale - great Neopolitain pizza.
If you have a car:
- Basta - better than Locale, and less pretentious too. Excellent pizza. And their bartender knows his way around Fernet Branca.
If you're going all-out:
- The Black Cat Bistro - $$$$
- Mateo - $$$$
- Frasca - $$$$$$
- Oak has the best bartenders I know of.
- The Bitter Bar is also good cocktail place.
- The Mountain Sun has 20+ beers on tap, all brewed there. The place to be if you like beer.
- Avery Brewing. If you have a car, you might want to bus anyway. They like hops and strong beer, and do both very very well.
- If you need a sports bar, The Lazy Dog has you covered.
- Boxcar Coffee Roasters
- Ozo
- The Cup
- Amante
- &c, anything but Starbucks. You shouldn't have to walk more than a couple blocks to find a good coffee shop.
The bar below the Boulderado (the name of which I cannot remember) has some truly spectacular people watching most nights.