Meh, I don't like Vail for anyone looking for hard terrain OR groomers. The only thing it has going for it is size (I should add that that's all IMHO. Clearly yours may differ).

I think Breckenridge has the best setup in the country for differing terrains; it's really easy for a groomer/blue skier to stay on Peak 7 all day and have fun, leaving the hike-able terrain, and bumps (on top of Peak 8, between Peak 8 & 9, and on the far left of Peak 10) to the experts.

Arapahoe Basin has the best tough terrain in the front range area, but it doesn't have the groomers, or the size.

Copper is actually probably a pretty decent hill, in terms of what you're looking for, though it lacks the on-mountain town that you'd get in Vail or Breck.

Telluride is still, IMO, the best skiing in the state, but it's a *long* drive from DEN.

I think my best advice, depending on how many days you planned to ski/ride, would be to stick with the Vail Resorts areas. If you got to Vail and didn't like it, you could take the ticket to Breck, Keystone, Beaver Creek or A-Basin and use it there instead. the Summit County areas have an excellent bus system between them, so it is relatively easy to try some different things if you stay in that area.