I find that most larger holes I do (home stuff, not business) are in sheet goods up to about 3/8" thick. For that, Unibits or similar single flute bits are GREAT. I often find that through-holes in thicker stuff can be done with em also...just be flexible and change your hole to match the maximum size the bit does. They take a LOT less horsepower than standard bits and are far easier to control...especially when you need to drill big with a hand drill.
One product that once you get, you can't figure out how to live without.
Koz