I learned that the block digging texture is actually directional, meaning that if you were to make an arrow as the texture for it, it would always point in the same direction. So that's what I did.
Here's a small texture pack to help you avoid opening that pesky F3 screen by being able to simply mine a block for a fraction of a second to see which way is north!
I tried to make it visually appealing, and have it visible on most blocks. I say most because the texture is more dim on darker blocks, but it's really only an issue on Black Concrete since it's consistently dark, unlike obsidian.