It's been about 5 years since my wife and I switched full-time to cast iron cookware. We've thrown out all of our Teflon and all that remains that's not cast iron are a few stainless pots and sauté pans.
If you haven't made the switch yet, you should make the switch:
- Easy to clean. Just quickly scrub under hot water with a stainless steel scrubber and wipe dry. A few times a week rub a few drops of oil in with a paper towel. Stainless spatulas are also easier to clean than the plastic ones you need to use with teflon.
- Easy to cook with. Cast iron heats incredibly evenly, meaning your pan won't have any hot spots. Apply a little bit of oil before cooking and you've got a perfect non-stick surface. Fried eggs, omelets, steaks are all wonderful when cooked in cast iron.
- No health or environmental concerns. Teflon breaks down over time and gets into your food, stainless can warp or rust if mishandled. Cast iron is virtually indestructible. Even if your cast iron rusts you can scrub the rust off, reseason it and it's as good as new. Your children's children will inherit your cast iron.
- Highly affordable. Cast iron pans are about half to a third the cost of equivalent non-stick pans and when you consider they last forever it's an even better bargain.
See also http://www.macheesmo.com/2010/07/ten-reasons-for-cast-iron/