I've got 2 aquariums set up:
A 35 gallon saltwater tank with a clownfish, valentini pufferfish and a damselfish.
A 45 gallon freshwater with an oscar, firemouth cichlid and a pictus cat.
I also have a 29 gallon I will be setting up soon.
I'd like to set up a nano tank sometime. I'd need to read up on them since I've never had one...Right now I'm happy with my 30 gal. saltwater tank.
FYI reefcentral.com is another excellent website for saltwater fish enthusiasts.