place your outgoing damage

    MiksScrollingBattleText (Curse | WoWInterface): This is a floating combat text replacement (though can be used in conjunction with Blizzard's as well) and lets you place your outgoing damage,

d3 items

incoming damage, heals,

buy kingdoms of camelot gems

and buffs gained/lost anywhere on your screen and with any animation you want. It really helps with screen clutter in AoE situations,

Little Empire Mojo

 and there's something very satisfying about making your crits sticky somewhere prominently so you can always have a view of the big numbers.