At early levels, out of PvP, it doesn't matter all that much. Unless you're broke a lot.. arrows aren't that expensive, but certain weapons blow right through them.
In PvP, I'd say you want an extreme weapon. Either very fast with a nice scope and all the haste effects you can toss on to machinegun stuff down; or very slow, for big hits whenever you have the chance to stand still. I don't know much about PvP, outside BGs though.
At 62, you gain Steady Shot. This is where it all goes stupid, because at this point, your DPS correlates *VERY* strongly to your modified weapon speed. It comes down the the point that, if you're BM, the first epic level 70 gun you'll get in the lowest 70 raid is better than *all* other guns game-wide.. for PvE anyway.