Clearly the best place for an escape key is the [`~] key
My WYSE doubleshots have an ESC key that went there on the original keyboard, and I put it there on my current one, because the colour theme matched. It's still mapped to [`~] though
Since it's QWERTY, I almost never use it.
I put my (cherry profile?) shamrock keycap on my [Delete] key for colour-reasons, and because the profile matches the rest of the keys in that area better.