I like Keystone or Breckenridge.
Be sure to pay for a lesson. If you've never skied before, you should be able to cruise some green runs after a full day lesson. If you try snowboarding, it will be three days of intense pain and suffering before you "get it" and find the heel and toe edges. But, after the three days of pain, it will be fun.
If your kids are skiing, I recommend that you ski also. I've found it impossible to snowboard with the kids while they're skiing. Kids will pick it up much faster than you will because they're probably in better shape but most importantly, they're closer to the ground and don't have as far to fall.
One other tip, if anybody has issues with altitude, a heart condition, etc., I recommend trying a place at lower elevation like Alyeska resort outside of Anchorage, AK where the runs end just above sea level. One of the main challenges with Summit County, Colorado for most flatlanders is the altitude. At Keystone/Breckenridge, base elevation is over 9,000 feet and by the time you get to the top of the mountain, you're looking at 11,000 - 12,000 feet. If anybody is not in good physical condition, that altitude will kick your butt.
Also, don't know how hard you're planning to party but... be sure to drink water and limit the amount of Colorado Kool-Aid you drink. Even when you're cold, you still need to be drinking water. Colorado is very dry and the altitude and sun will really take it out of you.
Also, goes without saying, in a large group, somebody is going to have an incident. Be sure everybody has everybody else's contact details, and be sure everyone has their health insurance details.
Lastly, shop around for deals. When I took my kids to Alyeska, I found an amazing late season deal through Costco. We were living in California then so our Spring Break wasn't until the first week of April.
Otherwise, enjoy!