there is a sh#tload of good stuff up here; lots of nat forest stuff west/north of boulder. then again, i've ridden down your way a bunch. great stuff there, too. i don't drive down south to ride much, because i have so much up here! not as much close to town, but within a half hours drive, i've got a lot. and there are a lot of *very* fast and talented riders in and around boulder.
disclaimer: i do not, in fact, live in boulder. i'm in longmont, because i'm to poor for boulder, and not one of the beautiful people.
the best riding up here is not the open space stuff. much of that is good, but pales in comparison to the off the beaten path/not mapped stuff up higher.