Really the easiest Heroic instances are just that, the easiest.
Slave Pens, Underbog, Steam Vaults, Mechanar, Botanica, Ramparts are all pretty easy.
If you have a good tank and crowd Control Magister's Terrace is pretty easy too (but a lot of people still have a big phobia against that place)
With a good pally tank you can also find Shattered Halls to be very easy, but other tanks have trouble in there specialy without much crowd control.
Heroics are overrated, if you have a decent tank its really not hard to heal in them at all, crowd control of coarse makes it easier, knowledge of the instance really helps (nothing worse then bringing a party member thats like sweet just hit 70 today and i did enough quests when i was lower level to be able to do heroic already, first time here lolol fun right...).
Generaly though in heroics it goes like this, Warriors eat hits well but lose agro on his off targets often and you may need to heal a dps or yourself and pray tank knows it is his job to save the day. Druid tanks generaly eat hits ok and have good armor but don't mitigate like warriors and pallies so sometimes you really have to spam heal them, they also seem to do a little bit better on tanking multiple enemies.
For warrior and druid 1-2 CC in group helps a lot, but if you have a pally you can get away with 0 CC, pallies generally have lowest amount of health specially newer 70 pallies, there armor tands to be less for a bit too, but you just gotta spam heal them sometimes having to use Lesser Healing wave, you really can not neglect pally tanks too much at all, but they tank many enemies with ease.
Heroics get easier and easier to heal from here, i would say stat priorities are +healing, mana regen, int and thats pretty much it stam is always a nice bonus though. The better your +healing is the better your earthen shield is which really makes things easier to do, with a stacked tank and a good amount of + healing you may not need to heal much at all for some pulls.
Good luck and have fun in your heroics.
Edited, Jun 16th 2008 10:16am by jmfmb