I think #6 looks great but would suggest making the type itself bigger to span across the cube so you have the blue on left side and cube on right (without splitting the words too much)
And my second favourite is #1, got to say it was a tough call between the two, some really great ideas there Nathan, I bet you're really pleased with them!
Greg
EDIT- I'd also either have both the lowercase e's like the first one in blue or both like the second in cube, having one with the cutout and one without may look a bit odd as both the 'B' and 'b' have the cut-out.