I also was a fish and reptile specialist at a local pet store, and from my personal experience (if you haven't gotten something already) I would recommend a bearded dragon. Lots of snakes are very easy to care for and can have interesting personalities (sometimes you don't see it right away and they have to grow on you), and Blue-tongues seem to be the most personable skink I have had the pleasure of working with, but bearded dragons are by far the most curious and attentive lizards in the store in my opinion. One of my friend's dragons loves basking outside in the sun so much that it gets noticeably peeved when you pick him up to go back inside (but never bites). Another plus is that they're captive bred and usually used to people handling them. A 40-gallon breeder is perfect size for one (that's what mine is in). Leopard geckos and cresteds (which I also had in the past) can make great pets, but normally they're nocturnal, and don't always adjust their routine to suit your viewing pleasure (plus cresteds crap all over the glass walls of their cage so you have to clean it really often.
I hope this helps if you still are looking for a pet!