If you have a heater and a filter go with a couple of Pea puffers.

I'd be a little careful with the betta and the angel, your betta might go after his fins or vice versa, depending on how agressive your angel is.

as usual, your wife is right ;) :razz:

Ok i have found a small school of cardinal tetra's always look nice.:biggrin:

betas also seem boring in bowls because enven tho they will live and survive at lower temps they would prefer 80ish temps.

i agree with this.

I have a betta in the same tank (heated 3g Tall) and he's very happy, he's been in there for almost a year now but before that he was in a 50g with many other fish and before that he was in a 5g with a few neons. He's been around for a while now :razz: We've had him for 3 years this january. He fights with his reflection alot but I think it's to pass the time :mrgreen:
I also agree about the little puffers, they are very cute! Perfect for a litthe tank.