Klog thats fine if you're in a raiding guild who are clearing content 4 nights a week but I don't even have two 264 weapons yet for my main spec. If I were to spec combat just to bring a 4% raid buff to what? another three maybe four dps in 10 man i'd knock off about 4-5k of my own dps. You may be getting the drops to have two viable spec. But i'm not, when I do then sure.
I dunno Yk, Blizz just seem to have trouble with the Sub spec so they're just leaving it untill a revamp in Cata we all assume. Theres some interesting levelling and pvp specs I could link for you but they won't be as good as the other two trees.