This wholly depends on where you are with your mana regen. As of now, haste is the new druid god IF and only IF your other stats are met (spellpower/mana regen).
Your goal is to hit the haste soft cap without sacrificing your spell power or mana regen. Since Innervate is only a 3 min cool down, judicious use of this can help you balance your mana production out if your running short. Also your healing style will dictate how well you use your mana pool.
My personal goal was a <1 sec global cool down. I have met that and still rarely if ever run out of mana even on the longer boss fights. I do gem spirit in the form of Purified Dreadstones but that is all. We gain plenty of spirit from our gear, trinkets and weapons as it is. My yellow sockets are always Reckless Ametrine and red is Runed Cardinal Ruby.
As my gear and gemming sit now, I am at 1330 spirit and 769 haste (unbuffed).
So, the short answer, don't gem specifically for spirit unless your wearing the completely wrong gear!
