Colorado has a lot of variety. So it depends on your discipline and what time of year you plan to be coming though. Also how many days are you setting aside for Colorado. The gang here has put a few maps together of various places. While there is pretty good riding in Denver and C Springs, the two listed for Colorado, neither of them is the best Colorado has to offer.
I am leaving in August and plan on doing Tsali, Raccoon Mt., and a couple others TBD on my way to Colorado and then Moab. I have made a sort of rough draft of my schedule and planned on hitting Co Springs for a couple days. If there is a spot that I must hit let me know. I would say my discipline is just trail riding (All mountain?). I love going fast and doing some downhill ish stuff. I am down for pretty much anything though. Thanks for the comments.