Santa Fe Ski Basin is a decent little mountain that is not all that "little" - 7 lifts, 1,800 vertical, 660 acres. Average snowfall is 220 inches, but some years have yielded more than 300 inches. The mountain is 15 miles northeast of downtown on highway 475, so it's an easy day trip.
They have a decent kids' ski program and an area for kids under 5 to ski/play in snow. With the exception of the Christmas and New Year holidays and NM & Texas spring breaks (early to mid March), the mountain is rarely crowded. There are five main lifts and numerous back-country trails to ski.
For those looking for something else active to do, there are a number of spots off the Ski Basin road for snowshoeing and/or cross country skiing. As you are driving to the mountain, you'll know the spots by the number of cars parked on the side of the road. About half way up the mountain is a good rental shop, Cottam's Ski Shop. You'll save some cash by renting here or in Santa Fe.