My two go-tos for now are
Hugo Boss Dark Blue and
Giorgio Armani Acqua Di Gio. The Armani is fresh but relatively understated (and can therefore be used in most situations) and the Boss is a bit stronger but not overly musky (smells a bit like Coke at first; only way I can think to describe it). I also have a pretty bright-smelling
Nautica cologne, but I think I bought a knock-off and it only lasts for a few hours so I use it a bit less frequently.
Unless you wear cologne every day, I don't think it's necessary to have more than a few options, especially if they're all quite different from one another.