A 100W heat panel would use the same amount of electricity as a 100W light globe if it ran for the same amount of time. Heat panels are a bit more efficient, as are ceramics. The savings probably aren't going to be very big however, it's more the cost of replacing the globes every 2-3 months for incandescents and 1-2 years for ceramics.
For those who disagree with my idea that they are more efficient (I know from past experience that you are out there,) I'll explain. A light globe turns electrical energy into 2 diferent types of energy (3 if you include the small amount of sound they make.)
1) Light energy - about 5-25% depending on what source you believe
2) Heat energy - 75-95%
The light energy is then absorbed by various surfaces and turned back into, you guessed it heat energy (mostly anyway)
However, both the heat and light given out by a light bulb are non directional. If you use white melamine cages, a fair bit of both these is reflected by the melamine and goes out the glass door. The energy that does this then heats up the room, not the enclosure. A heat panel or ceramic converts almost 100% of it's electrical energy into heat. This heat energy is fairly directional and is directed straight down, where it can be absorbed by the hide placed directly below or a basking rock or piece of slate. I've never done or seen any studies to prove it, but I reckon you'd get a 5-25% increase in efficiency by using one of these heat sources. Mind you, a reflector IR globe pointed straight at a peice of slate is probably going to be the champ...