In my opinion it's Type-F

Because:
* It's bi-directional
* It's grounded and ungrounded plugs use the same socket
* It's already widespread
* Your fingers can't touch the live wire as you're plugging in a wire
* Low footprint

Because:

• It’s bi-directional

This is very convenient, and not a problem in 99.9% of cases, but there are some devices where it’s important to not have the hot and neutral wire swapped