It's an excellent question Justin. It prompted me to go down to the shop and measure my outfit.
I was told by an old Tennessee gunsmith that you should be able to touch the jaws of your vise with your elbow, standing next to the bench. So I made my bench 36 1/4" off the floor, and the jaws of my 6" machinist's vise is 44 5/8 above the floor, which is covered with a 4' wide rubber matt 16' long. the rubber matt saves chisels when they drop or roll off the bench, and also, perhaps more importantly, saves my old back. I framed up my bench to utilize 1 sheet of 3/4" x 4' x 8' plywood ripped lenthwise. So my bench is 24" wide and 16' long. I employ a tall stool/chair when I am reloading and doing fine work at the vise like chequering and engraving. Be sure to install more lighting than you think you'll need. And speaking of lighting, you may want to go with led or florescent, but include an incandescent light over your vise. It is imperative for chequering when you turn out all the shop lights except for the one incandescent bulb. Doing so enables you to see your lines more clearly without eye strain.
A bench is a great place to lay things down, and will quickly become a clutter of partially finished projects that didn't get cleaned up and tools put away. I'm terrible for this, and must make a great effort to clean up after myself. There is nothing that will take away your creativity and drive more than having to face a cluttered bench, is there, Daryl.