not much - the animas in NM is barely floatable but not really that scenic or fun just riffles
cataract canyon is the best bet for whitewater - logistics are a pain - either you paddle 50 miles of flatwater or pay for a jet boat ride in - then there is quite a bit of flatwater at the end as well - very cool canyon though - make sure you get the 30$ permit - they do enforce it and it isnt cheap to get caught -
you can also float the mellow stuff above Moab on the Colorado it is all class II
Gunnison Gorge still going - the hike in tends to reduce the traffic on the river Pay the folks at pleasure park for the shuttle if it looks like rain - the road in can become impassable when it gets wet . I had to leave a truck up there one year and drive back the next weekend to get it.