Head :
Cryptstalker Headpiece31 agi, 2% crit, 3 mp5.
Neck :
Stormrage's Talisman of Seething2% crit, 26ap.
Shoulders :
Cryptstalker Spaulders29 agi, 1% crit. (was torn for these and pvp ones, but seeing overall hit from gear, these are better)
Cape :
Shroud of Dominion1% crit, 50 ap. (sadly, tbh, barons cape from strat ud is going to last till you get this).
Chest :
Cryptstalker Tunic45 agi, 1% crit, 1% hit, 4 mp5.
Wrist :
Cryptstalker Wristguards26 agi, 1% hit. (always the worst stated slot).
Gloves :
Marshal's Chain GripsHorde Version21 agi, 1% crit, 4% MS dmg. (runner up would be t2, but the 4% MS dmg pushes these over those)
Waist :
Belt of Never-ending Agony1% crit, 1% hit, 64 ap.
this was the one leather item that surpassed mail items. The runner up, t3, was less than the overall stats on this one. T3 gave 23 agi, 1% hit/crit, which converting the agi to ap, it was 18 less than the leather belt. As for the agi to crit, it would only give near 1/2% crit, which imo, 14ap beats. Also, quite a fitting name when going against melee for it.
Legs :
Cryptstalker Legguards42 agi, 1% crit, 6 mp5.
Boots :
Cryptstalker Boots33 agi, 1% hit.
Ring 1 :
Signet Ring of the Bronze Dragonflight (Exalted)
24 agi, 1% hit. (basically exact same stats as Master Dragonslayer's Ring, but the % crit from agi pushes these to be better).
Ring 2 :
Ring of the Qiraji Fury1% crit, 40 ap. (Master Dragon is also a close call here, but overall stats would put us past optimal +hit from gear if we did. The 1c/-8ap is a better choice here).
Trinket 1 :
Drake Fang Talisman2% hit, 56 ap. (sad but true).
Trinket 2 :
Blackhand's Breadth2% crit. (even sadder, but still true).
FD trink swaps would be
Earthstrike/
Slayers Crest/
Jom Gabbar?
Main hand weapon :
Hatchet of Sundered Bone1% crit, 36 ap.
Offhand :
Kingsfall16 agi, 1% crit, 1% hit. (good luck prying this from melee's dead cold hands).
Ranged Weapon :
Nerubian Slavemaker1% crit, 24 ap. (oh baby).
So now, lets break down the stats you gain just from the gear alone.
[stats done while I was playing alliance; horde won't get the +kings buff stats mentioned]
Agi : 267 (321 with kings)
Crit : 16% (+6% from agi with kings)
Hit : 9%
AP : 346 (+534 from agi)
Set bonuses : 6p - +4s to rapid, +50ap, +50mana on crit.
I won't go into detail about the enchants, but I will mention the zg head / legs ones since they apply to hit %. You'll be at 10% hit overall once you got them, which is unavoidable since there is no other gear that is better than this, that doesn't have hit on it. Nothing about talents in particular except for the 5% to crit, which would boost you to 19% crit before adding in the crit you gain from king'd agi (the 6%, which would boost you to 25%).
In all, the only piece of gear I really had an issue adding was the leather belt, which was the gain of 14ap over 1/2% crit. But I know crit has less weight the more you get it, yet ap and agi never do, so I was fine for the trade off.
Let me know if I missed anything, but I'm pretty sure this is the best stuff you can get.
Edit: Added Stormrage. (thanks to gaz/corn)