628 haste=39% increase in casting speed.
Spells:
Lightning Bolt: 2.5 second cast + Lightning Mastery Talent = 2.0 second cast + 628 haste = 1.2 second cast
Healing Wave: 3 Second cast + 628 haste = 1.5 second cast
Lesser Healing wave:1.5 second cast + 628 haste = 0.903 second cast
Chain Lightning: 2 second cast + Lightning Mastery Talent + 628 haste = 0.903 second cast
Now to get these numbers you must strive to get +spell haste gear. You will need the top gear from Sunwell, T6, S4. Here is the list of gear you will need:
HEAD
Brutal Gladiator's Mail Helm
NECK
Gaurdian's Pendant Of Subjugation
SHOULDER
Erupting Epaulets
CLOAK
Cloak of Arcane Alacrity
CHEST
Garments of Crashing Shores
WRIST
Skyshatter Bands
HANDS
Gauntlets of the Ancient Shadowmoon
WAIST
Skyshatter Cord
LEGS
Chain Links of the Tumultuous Storm
FEET
Skyshatter Treads
RINGS
Guardian's Band of Subjucation
Guardian's Band of Dominance
TRINKET
The Skull of Gul'dan
WEAPON
Brutal Gladiator's Swift Judgement
For the shield and second trinket choose what you would like. The great thing about this set up is that you get one of the Skyshatter Regalia set bonuses. Also, every piece of this set is Mail, so you don't lose armor. For the gem slots you'll want to use Quick Lionseye and Reckless Pyrestone.