Sounds llike some of you are interested in vivariums.
I had a 55 gallon with a waterfall & 5-gallon pool (planted, with a beta) and 3 dendrobates leucomella (black & yellow) dart frogs in the land part (and sometimes in the water part). It was AWESOME!
You might consider dart frogs. Dart frogs make terrific inhabitants - they're dinural (awake during the day so their singing doesn't keep you up all night), active, usually out in the open, and very interesting to watch. They eat bugs, too -mostly crickets and flightless fruit flies. And, yes, I'm referring to "poison dart frogs" - but if you feed them properly, they aren't poisonous. (The poison is metabolized from ants & termites they eat in the wild, so dont' feed 'em ants or termites.) A properly fed captive-bred dart frog (the only kind you should buy) is not poisonous - but I'm not recommendinding handling them or feeding them to your kids or pets. If you're interested in dart frogs, do your research before you buy them.
I'm the web designer for Vivarium Concepts (http
/www.vivariumconcepts.com) --there are lots of photos there of vivarium setups, and you might look at this site for ideas. I'm going to set up an vivarium with imitators (thunbnail-size dart frogs) in the next month - I've waited almost 2 years for them, and I am really excited about them. It'll probably have a water feature, but not an actual pond with fish.
I've also had day geckos in a vivarium - also very interesting. If you go with a small enough reptile/amphibian, you can watch very "natural" behavior. The problem with the juvinile water dragons (which are fascinating) is that they grow up big.
Leslie