Top lane tanks need a first item

Every other class of champions has a first buy item that is near 100% gold efficient and grants a large portion of the stats they need: Trinity Force, Morellonomicon, Black Cleaver.

However, the effective first buy for true tanks (not juggernauts) is supposed to be Sunfire-- an 80% gold efficient item, on champions whose kits are already not designed for last-hitting or dueling.

This discussion is only for top lane, as the tanks who are most effective in the jungle tend to have different strengths and buy Cinderhulk anyway.