Mid: Granary for sure. Very dynamic ways to rollout to as both demo or combo. The big differences in height make it really interesting too. Process would be my second choice.

Second: Badlands' spire is really unique and adds an element of map design you just don't get elsewhere. Gully is good too.

Last: Gravelpit has so many ways to enter last, in a big arc. A huge variety of offensive and defensive plays can work here. Gully is kind of like this too, with multiple ways of entering last, but no big differences in height or a crazy placement of last's cap point.