I will always choose the lightest wheel that I can for the way I ride. durability is only as good as your maintenance schedule, IMO.

Get a wheel built on a good quality, self serviceable hub (DT350 would be great) and some double butted spokes to a rim. if you need it to be stronger, higher spoke count would help over a heavier rim... again in my opinion. if your always bashing the rim off a curb or riding down stairs a slightly heavier rim might help.