I've been using IceHUD for ages, tried DKIRunes/Diseases a few weeks ago and didn't like them so sticking with IceHUD, I found the disease monitoring almost worthless since they get renewed with the Blood Boil proc. For cooldowns, I just use a custom action bar to display those, nothing fancy. Also not sure if I should get an absorb tracker, I'm not sure if it provides any actionable info, since I don't have issues with Death Striking anyways.
i personally like the standard blizzard action bar and than i use x-perl unit frames because they have a nice rune bar and quartz for my casting bar. also i have mikScrollingBattleText which show the damage taken and done around my toon.