Skiing in Breckenridge is awesome and there's plenty of places around that will do a great job of fitting you with all the equipment that you'll need.
Equipment: Alpine Sports treated us very well so I would highly recommend them for both their service and their prices.
Be sure to check at the desk where you stay as a lot of places have discount coupons.
Quandary Peak, at 14,265 feet, is one of the easiest Colorado 14er to climb. It is a 7 mile (round trip) hike with about 3500 feet in elevation gain. It is technically easy, but at that high of an elevation, it can be fairly strenuous. I am not an athlete by a long shot, but I was able to successfully summit. The route is easy to follow and has amazing views of the mountains and valleys around. The view from the summit is beautiful. In the summer it's a fairly popular trail and you're bound to see many other people. I wouldn't try it in the winter unless you have lots of winter mountain hiking experience and the proper equipment.
Equipment: In the summer, you need good hiking shoes, lots of water, sunscreen and warm clothes. You should try to get acclimated to high elevations for a few days before trying to hike this mountain (don't do it as soon as you get to Colorado). Start early and leave early (thunderstorms often suddenly start in the afternoons and you don't want to be on the mountain when lightening strikes).
Hadn't done any downhill skiing for a very very long time. Happened to be in Colorado, and had a pal along who was into snowboarding. The visit turned out absolutely fantastic! I rented all the gear (skis, boots, poles, skiing pants, jacket) as I didn't have any (apart from my leather gloves :). Turned out a bit expensive, but well worth it - really good service and all slopes were in excellent condition. Would visit this place again any time.
The slopes were great, the snow was great, and the lines were small. New to snowboarding, we took a day long group lesson that was very helpful.
Ski all day on this vast ski mountain, don't be afraid to venture up above the tree lines it's amazing.
Equipment: Wear warm clothes, sunscreen and take some type of antiemetic to fight altitude sickness.