Critical Strike - Increases the chance for each heal and damage ability to crit, this includes all HoTs.
Haste - Like other classes, haste reduces your cast time and lowers your GCD. In addition, it also benefits our DoTs and HoTs, by giving us a partial tick at the end of their duration.
Versatility - A fairly bland stat that increases your damage / healing, while also reducing damage taken.
Personally, as horde, I would pick Blood Elf as my race for its utility with Arcane Torrent and the fact that all races are extremely similar in power.
As for alliance, it’s likely to be Void Elf or Night Elf, for their respective racial abilities.
Intellect Gem: Leviathan’s Eye of Intellect
Stat Gem: Deadly Lava Lazuli
Food: Mech-Dowel’s “Big Mech”
Healing Potion: Abyssal Healing Potion