Which is better?

Question
I was going to purchase a first time pet for my brother. And i was going to let him choose, so far we are down to either a Leopard Gecko or a Bearded Dragon. But the problem is we only have a 20 gallon tank. now would it be better to raise the bearded dragon (he really wants one)in the tank and then upgrade to a bigger one or should i get him a couple geckos instead?

Answer
Let me start by saying both are great animals.  The leopard(s) would live forever in the 20 gallon and would need only normal cage set-up and perhaps an undertank heater.  The bearded dragon would definitely outgrow the 20 AND will need both heat and UVB provided by overhead lamps.  So your set-up and cage of the bearded will be much more expensive than the leopards.  Beardeds are definitely worth the expensive if you can afford it but be prepared to spend at least $100 just to set up the tank. Further, the UVB lights must be replaced at least once per year depending on type (check the box).  The leopards could be set up for $50 or less and regular light bulbs or even window light is fine for them.