Lizards make the best display animals, because they are like fish, most are diurnal and they are always out and about doing stuff!
Nocturnal snakes can be good display animals as well though. Especially arboreal ones like Emeralds, GTP's, and Jungles! A nice Carpet or GTP in a display tank can be the centerpiece of a room!!
I wouldn't mix species though. Just not a good idea in a relatively small area (relative to the habitat in which they are from).