Sooo many options and you will probably get a ton of answers.
If I were you I would browse through the show and shine section and take a look at the black cars. Pick the one with the finish you like the best and find out which wax or sealent they used.
A good sealant like Duragloss 501, Collinite 845, Detailers Pride Poly Coat, Optimum Opti Seal, Finish Kare 1000p
Waxes such as Fuzion, Souveran, Sig Series II, Optimum Car Wax