Best place to ski/snowboard in Switzerland in early December with guaranteed snow?

My girlfriend and I are in planning a trip to Switzerland in the second or third week of December 09' before Christmas and would like to know where the best place for skiing and snowboarding is with guaranteed snow in the given time, or should we wait to go the week of New Years and if so still where? My other question would be, is it better to stay in a hotel or chalet/apartment? the places we are currently interested in are Zermatt, Saas Fee, Grindelwald, and Laax.