Prior to Friday night I had been waiting till I got 150 mp5 unbuffed to start stacking haste. After becomming one of the luckies SOB's ever and grabbing my 3 pieces or T6, I thing its safe to say that its time to stack some haste. So here we go. I am currently at 58 haste from gemming alone. I am trying to weigh my options here and get around 180-200 haste while not sacraficing heal and mp5. I am only considering items that are, of course, upgrades and available in hyjal/bt content. I am mostly using this as a reference to myself but feel free to chime in. 

Neck:

[item]Brooch of Nature's Mercy[/item] from Eagle boss ZA - 33 haste

(i will lose 7mp5, gain 12 healing, lose some stam)

Waist:

[item]Naturalist's Preserving Cinch[/item] Supremus - 37 haste (17 gain)

(lose 10 mp5, gain 7 healing) this one is Meh imo. 

Helm:

[item]Skyshatter Helmet[/item] w/ 10 haste gem - 10 haste.

(gain 2 mp5, lose 2 healing)

Legs: 

Once I get T6 helm to maintain set bonus:

[Sun-touched Chain Leggings] w/ 10 haste gem - 10 haste

(gain 5 mp5, lose 5 healing)

Cloak:

[item]Shroud of the Highborne[/item] Illidan - 32 haste

(gain 15 healing, lose 7 mp5) 

Gloves:

Once I get helm to maintain T6 bonus

[item]Botanist's Gloves of Growth[/item] w/ 10 haste, 11 heal 2mp5 - 47 haste

(lose 4 healing 8 mp5)

So the easy upgrades include neck, trinket and wrist. Getting the PVP neck, trinket and getting the bracers crafted would put me at 154 haste sacraficing  6 healing and 7 mp5.  The rest are drops so it they are situational. Again if you notice haste upgrades I've left out please let me know. Also many of these are out of ZA so if you need a healer for any of your ZA runs you know who to ask.

Note that I have factored my talents into this w/ 30% of int being counted in as +healing. 

Edit: Added 
[item]Botanist's Gloves of Growth[/item]. I now have [item]Living Earth Bindings[/item] and [item]Battlemaster's Alacrity[/item].

Edit: Removed [item]Blessed Band of Karabor[/item], [item]Guardian's Pendant of Reprieve[/item],  [item]Signet of the Quiet Forest[/item], [item]Enamelled Disc of Mojo[/item], [item]Cloak of Ancient Rituals[/item] as I now have them all. Muhahahaha. Going to add a few pieces from entry SWP soon.