- Used them once and was quite happy.
Also, a lot of the resorts do have central reservations services that will put together a decent deal (yes, including airfare), if you have a specific destination in mind. Aspen comes to mind as having been very helpful to me in that regard for a trip last year.
I think whatever you do, while you might shop initially online, I think you get better response if you phone and talk to the reservation people directly, particularly if you are trying to find a 'deal'. Sometimes moving the trip by one day can make a big difference on air fare or lodging costs, or they may know of a lodging place running a deal - you can have these kind of discussions and give and take if you talk directly to a person.
lists a number of different companies that offer packages, if you want to try to dig up some others.
Good luck! Planning the trip & getting a good deal can be part of the fun!!!