Check out http://geckoforums.net/, it is a fantastic site to go and learn all could ever want to about leopard geckos. As for beardies check out http://www.thebeardeddragon.org/.

Both are quite hardy lizards with some fairly drastic husbandry requirements. Bearded dragons like to bask in the sun so a heat lamp is required and they also like to eat fresh veggies. They are fairly docile and I have even heard of people having leashes to actually walk them. They also get to be about twice the size of a leopard gecko.

Leos required an UTH(under tank heater) and like to hide during the day and are mainly active at night. They eat live bugs such as mealworms or dubia roaches which may be a problem for some.

For each of these lizards I would say a 20 long tank would suffice for both with a 10 gallon being to small for an adult of either type.

This is to just give you a quick few facts about each. If you have more questions please feel free to PM me any time.

-Greg