Moonkins benefit from stacking intellect

Stacking intellect is a stupid idea. Don’t gem for it, don’t enchant for it, don’t itemize for it - just don’t do it.
I already know what you’re going to say, “But when I socket/enchant intellect I also get crit, damage, MP5 and, of course, the mana.
Yeah, I know. I get it. Intellect gives you some mana and a minuscule amount of other beneficial stats.
Here’s the deal.
Moonkins were given a talent called ‘Lunar Guidance’. It was meant to compensate for the lower damage values that moonkins typically have. This meant that while moonkins were stacking damage, we would receive extra damage from the incidental intellect that is itemized on practically all caster pieces.
Lunar Guidance is not justification for stacking intellect at the exclusion of the more important stats, but rather it’s a bonus - something to keep us viable against other casters.
As mentioned earlier, the best stats for a Moonkin druid are Hit > Spell Damage > Spell Haste > Spell Crit. Although you are correct that intellect provides a minuscule amount of regen, damage and crit per point, you need to understand that you could NEVER get the proper amount of hit/damage/crit/regen by stacking intellect alone. Counting on intellect to satisfy gaps in your stats is counter productive - you’re spreading your key stats too thinly.

Leather is better than cloth:

Not always.

True story; I was on the PTR the other day with my Moonkin pal Florana. We were discussing many Moonkin-y things when we were accosted by a “balance druid”(and I use the term loosely) who was wearing a strange mix of greens/blues/purples who informed us, rather frequently and loudly that we were ‘ghetto moonkins’ because we had cloth pieces equipped. It was also explained to me that a grey leather belt is superior to an epic cloth belt - because druids should never under any circumstances wear cloth. It makes you a bad person. Wearing cloth makes you want to kick puppies and chew with your mouth open in public places.

No, seriously - most balance druids aren’t this extreme, obviously, but there is a stigma attached to the usage of cloth. As I mentioned earlier, our armor multiplier in Moonkin form basically takes a piece of cloth and puts it up to leather armor level - and besides that, armor is a useless stat in PvE.

Wear whichever piece has the best stats. Don’t choose leather simply because you have an irrational dislike of cloth. Sometimes you really won’t have too many options.

Source: http://forums.worldofwarcraft.com/thread.html?topicId=6286658964&sid=1

Some other major points.

Moonkins are called OOMkins for a reason.

This was true…2 versions of the game ago (Vanilla WoW). With TBC, Dreamstate and Intensity were able to be picked up in the same spec, and Spirit mechanics changed. These two changes in large part shifted moonkins away from the old nickname. With Wrath of the Lich King, even more changes have occurred to pull us away from the term OOMkin. Moonkin form gives back 2% of mana on crits (please note this does not make crit our best stat.), Omen of Clarity has been changed to affect all spells/abilities, and More classes outside of shadowpriests are getting regen abilities, that are going raid wide. If you still have mana issues with all these changes, it’s the not spec that’s the issue. There’s even theories that will take points OUT of regen talents as your gear improves. OOMkin is a dead term, has been since TBC. Anyone that calls you an OOMkin, should be simply laughed at.