I have one of each. But, if you only have a few hours to play each week, and you still want to get through the high end content, I can totally see having 2-3 of the same class so you can maximize your drops and keep at least 1 fully outfitted character. Personally though, I find it hard to stick with one playstyle constantly...this game is too repetitive and the different classes/subs really make a difference in breaking up the monotony. We will have had 6 months to get max level between DLCs (assuming a May release for HoW). Also, it really helps to play other classes just so you know their capabilities when teaming up or competing in the crucible.