As far as Tahoe goes (and not including backcountry spots)....Squaw is the best (in my opinion) mountain in Tahoe by far, but if cost is a concern then Alpine has for the most part the same quality terrain, just a smaller mountain. If you like park, then I would say Northstar has the best park, but for any other skiing it's rather boring and flat (and it's also pretty expensive). South lake has the better party scene, but with the exception of Kirkwood (which is pretty far away from South lake anyway) the skiing down there doesn't even compare to what North lake has.