Horsetooth by Fort Collins mostly. Boyd Lake and Jackson at times. Occasionally Pueblo and Sterling but for the best water we go to Glendo and Guernsey in Wyoming.
You can get good water if you just get up early. I don't know about the Denver area lakes, but if you are willing to hit the water at 6am you can usually get 3 to 4 hours of decent water before the tubers come out. And you might get lucky in the evening to get another hour or so when it settles down again.