Leopard Gecko

Undertank heater is the way to go. You can get them at your local shop, or online. I'm friends with the people at the Beanfarm and have gotten my heaters from them.

I also use sand with mine. I have used Calcisand for them, but there are many different types (and colors) you can get. make sure there are hiding spots on both the "hot" and cool sides of the tank, and one of them is a little "wetter" than the other (to aid shedding). Definitely dust the crickets, mealworms, waxworms (only as an occasional treat), or whatever you're feeding them with a vitamin supplement. I use Minerall for mine. Other than that, Tanith's link should be very helpful. Tremper is considered the foremost expert on these guys, as far as I'm concerned.

Have fun!