haste rating is, by all the calculations I've seen, the worst rating to stack in terms of net performance.
is this for a sword rogue or a dagger rogue? clearly you need to mention this is for a rogue who has a slow, but high DPS weapon. i use daggers and i rely on haste to put out my numbers. haste = AP (i don't know the number).
i use white damage more then i do yellow. i'm all about (for our canadian friends, "abOOt") haste. the faster can hit a target, the more combat pot, poison, enchants (mongoose) will proc, thus producing more white damge with the least amount of engery being spent (having a fast weapon).
this is the foundation of dagger rogues (raid spec'd). if you don't agree with this, just look at my numbers. there are somethings that math can't show you until you try it out yourself.
if you're talking about the haste rating on the new ZA(ish) badge items, then you should make sure your hit rating is capped before you invest in haste.
i agree with lealla about pumping up the weapon ex. if you're a sword rogue. you won't need to hit anything from the back so weap. ex. would be logical. and the 5 points in SUB could be spent somewhere else.