Gary:

You should be aware that your halogen bulbs are using nearly as much electricity as regular incandescent bulbs, and most of the energy they consume is being wasted as heat.
Fundamentally, the primary difference between a halogen bulb and a regular incandescent bulb is that halogen bulbs have bromine or iodine gas in the bulb rather than an inert gas like argon. The halogens (bromine and iodine) react with the tungsten atoms that come boiling off the hot filiment and redeposit the tungsten atoms back onto the filiment, so that halogen bulbs don't darken with age the way regular incandescent bulbs do. Also, halogen bulbs operate at a much higher temperature so they use a quartz bulb rather than regular silica glass.

Still, you will realize a substantial electrical savings if you switch to either compact fluorescent bulbs or LED bulbs. I would consider compact fluorescent bulbs instead simply because their price is lower and the price of LED bulbs is still coming down. LED bulbs are supposed to last very much longer than CFL bulbs, so maybe LED is the way to go to save more over the long term because you won't be replacing bulbs nearly as quickly.