Personally, I like Mundo.
His Cleavers give him excellent poke and kiting in the laning phase, also useful for getting some tricky last hits on minions. And by the time he reaches level 6, he becomes extremely difficult to bully out of lane.
In addition to the HP and other Tanky stuff you want to build, I also like splashing a fair amount of CDR. Cause having lots of Cleavers increases your poke and kiting, and having your ult up more often make you especially hard to kill.
The only weakness in the current meta however. His Tankyness is Extremely reliant on his health Regeneration. And that can be gimped due to the popularity of Morellomicon. Grievous wounds really hurts him.