I would say to go for your original choice - I prefer speed to strength, really, and while strength may be optimal for dishing out damage, at higher level you are going to be using more from dice than from bonuses still.
That said, I would recommend Vital Strike feat tree as it will offset your inability to use your flurry of blows with your movement.
I'm going to have to disagree with this advise. Strength is way wore important than dex. My lvl 5 monk has a damage bonus of +11 for single attacks and +9 for FoB. Even at lvl 20 2d10 averages to only 10 points of damage, I'm already doing more than that at a fraction of the lvl.
Str also helps determine CMB and CMD, which you will need if you wish to perform any manuovers.
Wisdom is actually more important than dex also, it adds to AC and CMD, as well as your stunning fist DC.
I'm not saying completely disregard dex, but 12 or maybe 14 should be good enough. You still want a reflex save bonus.