Simply put, if you're visiting Colorado you should probably take the opportunity to purchase legal recreational marijuana from an authorized retailer. Accepting that, you don't want to fund the average burn out dealer superficially legitimized by a register and display case. To ensure your first condoned weed purchased is a good one, visit Pure.
Pure seems to enforce a policy of hiring only the most educated weed nerds. Such dedicated staff is a great asset, as they can point you towards exactly the sort of high you desire. Further, Pure does business solely by the merit of the product, not overhyped cannabis cups or ad campaigns, just superb marijuana grown in real soil and fresh edibles.
$10/gram isn't bad for the quality, but no price break for larger quantities means keep your purchases modest. Other locations are medical only.