I live in Denver; here's my two cents:
I strongly second the Riverdale Dunes recommendation. It's maybe 20-30 minutes from downtown. It can be overwatered at times, but it's still the best public course in the area.
I've never played Fossil Trace. If you're looking to play an Engh course, this is probably the one to try. The only other public Engh course in the area is Red Hawk Ridge in Castle Rock, which I don't recommend. Fossil Trace is also very close to downtown, 15-20 minutes tops.
Some others I recommend are: Buffalo Run (Commerce City), Heritage at Westmoor (Westminster), Fox Hollow (Lakewood), and Green Valley Ranch (Denver near the airport). They're all about 30 minutes from downtown. Don't expect greatness from these four, but they're all solid.
Buffalo Run is a faux links course designed by Keith Foster. It's gone downhill in my mind a bit since they've started to build homes out there (it used to be very isolated), but the course is good. Heritage at Westmoor is a Hurdzan/Fry course with 2 quite different nines--there are a couple weak holes here but I really enjoy the course. Fox Hollow has 27 holes--you should try for the Canyon/Meadow combination. Again, nothing tremendous here, 1-2 goofy holes, but you get a sense of playing in the foothills and it's quite scenic. Green Valley is a Perry Dye course. It's new (2-3 years old) and I haven't played it enough to say whether I really like it but it's worth playing.
If you want to go further afield, you might look at Golf Club at Bear Dance or the Ridge at Castle Pines North (Weiskopf). They're both CCFADs, $100+, but they have some good scenery and have some good holes. I recommend Bear Dance over the Ridge, but it's 10-15 minutes further south.