BTW.
In terms of PvP, full STR is better!~ I'm a full SPR archer (just level 26), and I pvp'ed a full STR archer - same level, same defense, same weapon (well I tried both cross bows and normal bow) and I lost in every battle, haha. When we use skills, he kills me first bu he only had like 1hp left (damn poison doesn't kill D

but when it's just shooting and no skill... I lose big time.
That's, of course, at level 26. Can't really say what it's like at higher levels.
But I vote full STR over full DEX because like Ralath said, they can be substituted with scrolls.