To choose someone or something that is very likely to prove beneficial, suitable, or successful. The reason why third party candidates don't usually get a lot of traction is because people want to pick a winner—not just make some kind of statement. Samantha is so warm and intelligent, and it's clear that she cares about you a lot. You really picked a winner, Joe. The design is clean and practical, but still elegant and appealing—I think we picked a winner!