Need help filling an empty tank

Okay, so i have a 40G breeder tank (Aquarium) that has just become empty.

I am trying to get ideas on what i should put in it. I have been wanting a big amphibian tank for quite some time now, and now i have a tank to do it with, but now i am stumped on what species i want, how many, and what kind of setup (that will be determined when i find what species)

I would prefer to go with some type of frog or toad. Nothing again Salamanders and Newts, and i am not opposed to looking into them, but Frogs are my first choice.

I would either like to do a fully self sustainable vivarium (which i know is pretty common for Poison Dart Frogs and Mantellas, but those are not my first choice)
or, and idea that i have been extremely fond of lately is a Paludarium, and do like 70/30 Water/Land, or 50/50 Water/land. But like i said, i dont know what species to put in there. preferably something that will go well in one of those two habitats, um, something preferably communal (so 2+) or something that will actually utilized the space if alone like a Pixie Frog or a Pacman.

This is my first post, so please yell at me if this is in the wrong place, but i have been lost on what to do for almost 2 weeks now. What do you guys think.

If it were me, I'd go for the 70% water, with African clawed frogs in the water. Plant the rest, put up lots of climbing structures, and then add a couple of Barking tree frogs.

This is my Biggest tank right now, and is kind of the center piece of my office. As cool as African Clawed frogs are, i think either something bigger and semi aquatic, or a colony of little guys and i can make it look nice going naturalistic. Nothing like turtles though as they like to tear stuff up. haha.

If I were you I would setup some Colbat Dart frogs. If you wanted to go cheaper in price with the above setup, you can certainly have Fire Bellied toads. I bred a pair in a setup like that with a filter in the water.