What (in your opinion) is the best single-shot cartridge out there right now?

Kind of a discussion I saw elsewhere, and I wanted to see what the fine folks on this sub thought. What do you think is the best single-shot round in use today? Think about its consistency, penetration, take down speed, accuracy, recoil, etc., and then choose the one you think fits the bill. What is it, and why did you choose it?