Colorado Resorts:

First, a general overview. These views might upset some people, because everyone has a favorite mountain, but most people are flying into DIA and renting a car so these comments are skewed for that.

You cannot go wrong with any ski area as they all have their special charms, but an informed choice can tailor your needs to the area. 

Most people will agree that the best single mountain is Vail due to its incredible size and varied terrain. That said, Vail is also one of the most expensive places to ski, sleep and eat (and yes, there are always exceptions) and most people have to take this into account. In terms of expensive (and also an excellent place to ski), Aspen has to be mentioned in this paragraph, but  Aspen is a former mining town and is also comprised of four separate mountains and they vary from small (Aspen Mountain/Ajax-great skiing though) to huge (Snowmass-though not as enourmous as Vail). While on the Aspen area, Buttermilk was the beginner mountain but now has incredible snowboarding terrain. Aspen Highlands is an excellent, often-forgotten advanced skiers mountain.

At the opposite end of the spectrum are countless smaller resorts that have a lot of appeal, especially to beginners or people on a budget. Eldora, Monarch and Wolf Creek (alphabetical order- chosen at random as there are others listed below) are but a few and each area has its charms and quirks.. Wolf Creek, for example, is noted for the most powder days and total amount of snow. Of these three, only Eldora (near Boulder) is easly accessible from DIA.

There is also a special category of "boutique" areas, mainly Telluride and Steamboat, that fall into unique designations. Many people love Telluride for its beauty and steep runs, and others  prize Steamboat for its tree skiing. They are more upper tier in relation to cost mainly due to their distance from the beaten path. Beaver Creek should be mentioned in this category although many feel it is a subsidary of Vail. The skiing is excellent here too, but it is even pricier (lodging and dining) than Vail.

The vast majority of people will access the resorts of Summit County (Arapahoe Basin, Breckenridge, Copper Mountain and Keystone) and Winter Park. All are within a two hour drive from DIA  - IF THE WEATHER AND CROWDS PERMIT. Crowds being the traffic on I-70 which is absoutely horrid on Saturday mornings and Sunday afternoons. Don't forget Loveland which is the closest area to Denver and does not involve a trip through Eisenhower Tunnel (not that this is a big deal, but Loveland is the closest).

Let's talk Loveland. Although a smaller area, Loveland has a nice selection of runs, reliably good snow due to its proximity to the Continental Divide and has an excellent availability of discounted tickets (check the web site). There is no lodging nearby, but Georgetown and Idaho Springs both have room availability.

In Summit County, Arapahoe Basin is the smallest and highest. There is no lodging, so day trips are the only way to get there. It stays open until June (usually) and has good late season snow.  Much of the skiing is above timberline so bring yellow goggles on snowy/cloudy days. A-Basin is very close to Keystone Mountain. Keystone used to be known as an intermediate mountain, but Vail Associates (its owner) has greatly expanded the expert terrain in recent years. There is a large selection of lodging at the base. Copper Mountain is right on Interstate-70 at the start of Vail Pass. Copper has a large selection of varying terrain and offers easy access to all abilities. The saying used to be "Party at Breck, stay at Keystone, ski at Copper" but those lines have blurred in recent years. Copper's Super Bee (6 person high speed) lift does offer a very fast access to great steep terrain and bump runs. On the far right side is the Union Creek area which is all beginner terrain. Breckenridge is the largest mountain in Summit, but also very popular which means, in general, longer lft lines. The town (a short distance from the lifts) is a beautiful example of a classic Colorado mountain town (mining town turned skiing town) and Breck has installed a new gondola to transport skiers from the parking in town to the bas of the area. Winter Park is located over Berthoud Pass, which can mean slower access, but it is also serviced by the Ski Train from Denver. Winter Park offers an excellent sub-mountain (Mary Jane) for expert skiers as well as a large selection of beginner and intermediate terrain in Winter Park proper. 

Many people who ski at Copper, Breck or Keystone stay in Silverthorne, Frisco or Dillon. All are in easy reach of four mountains and the Summit Stage shuttle runs between all mountains. This is the least expensive area for lodging and dining. Indeed, one can take a shuttle from DIA to one of these towns and access all the mountains without a car by using the Summit Stage. There are also many excellent restaurants and ski rental shops in these towns.

THE LINKS AND RATES BELOW ARE FROM 2005 (the notes above are as of Jan 08)....

1st place to look for discounts are Front Range (NOT mountain town) grocery stores (Safeway, King Soopers, Albertsons, etc.):

* 2005-2006 Peak Season Rate for adult (ages vary, kids and senior rates available) unless otherwise specified, discounts apply to non-peak season rates depending on date. Full rate information can be found on websites. No one really pays this rate as discounts can be found, see below.
** General dates provided, exact dates can be found on website and are based on snow conditions and weather.
¿ Guess
§ 400 lift served, 2400 snowcat served, not continuous dates open early in season.
Δ Popular/Crowded
∏ Denver Accessible for day-trip. All but Eldora are along I-70 route.
Λ Resort with lodging on-site and/or summer activities.

Ski Passes:

Colorado Ski Season Passes

Colorado Ski Resort "Four Packs"

Other ways to get Discount Lift Tickets