Winter Park is a great place!! Even on busy day's it's still less crowded than a lot of the other resorts in CO. I agree the Cirque is over rated (too much of a hike and out run for the short amount of terrain.) Hole in the Wall is great, especially with new snow, but it is fairly short. The trees are awesome and the BC stuff out the Hwy 40 access gate is incredible too! The park and pipe wasn't huge last year, but it was fun, and with intrawest redesigning it, it can only get better. If you're into bumps, stay on the Jane side (best bumps in the country!)
You mentioned that you're looking for powder and you'll be out there in the end of Dec....you're probably not going to find a lot of it (unless we get a some kind of storm) cause it's still so early in the season.
I love the place! It's fun, not very crowded, relitivly inexpensive, and you get a wide variety of terrain.
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Donkification