superteguoverload ;_;
But yeah, tegus are larger, very friendly docile lunks of a pet. They need lots of space, so not the best for someone who can't afford a 60 or 70 gallon tank in their bigger years.
@Justine66: ease of care, several of the already suggested lizards are similar in care requirements, apart from size of terrariums. Lots of bugs, occasional snack creature treat... water. Leo's don't need UV lighting, like snakes they're bottom heated. No sand substrate! mostly rock kind of area. Tiles and stones make good environment, several hides and a moist hide. Also, they need calcium supplement available all the time. Beardies are bigger, can eat mice frogs other lizards roaches bugs etc. They need a long tank to accomodate a max 3 ft length. neither are horribly climby creatures.
Turtles can be more difficult to care for because you need to worry about the condition of the water in addition to land mass, tank size, and food. A friend of mine fed the turtle smallish fish, one or two of which are now buddies in the tank because they didn't get eaten. Some lettuce now and again is a good supplement. Illnesses can be harder to detect, because they're in the water so much. some turtles will get something called soft shell, where they've been in the water so much that their shell has...well... softened. It can be very dangerous to their health.
Personally, I'd go with the Leopard geckos because they're smaller, you can house 2 or 3 together (never more than one male!), they get fat tails so you can go away for a weekend without worrying about feeding, and they're just so damn adorable. Smaller tank, more animals, more fun!
Just don't grab their tails.