I blogged a little while ago about Metering and Exposure. In the Studio with Studio Flash Strobes a Light Meter is critical.
When shooting outdoors I do tend to use the expose to the right rule, but this is dependent on the contrast and dynamic range of the scene.
Whether you use the expose to the right technique, follow your histogram, or clipping warning, what matters is what works for you. An exposure that is technically correct may not give you the image you want, there is a degree of subjectiveness.
In the studio I follow the light meter, outdoors, well, auto bracketing is my great friend. The histogram and clipping warning advise, but if you tweak the jpeg settings you can find your histogram and clipping warning change.
Develop a technique that works for yourself.