I have been playing with Adobe Lightroom for the past couple weeks and find the control amazing. For exposure indicator I really like how Lightroom handles this.
When you are in the Tone curve, you can click on the diffused highlight... and look at the reading.
In this example I've placed my tone selection tool on the diffused highlight and I'm at 80% (which is where I would like to be for proper exposure).
This is great when shooting tether, but also great for correcting exposures when not shooting tether. Either way it's very simple and straight forward and very precise. Just select the diffused highlight and click and drag