Here's my current work in process. I'm still a noob in modeling, and I'm using this hobby (aquariophily) to design stuff I want to build and at the same time, learn 3D. The following was done with blender 2.43 and Indigo 0.6 (over 6h on my Core Duo laptop):

I would greatly appreciate your help on further improvements. The water seems strange to me, and I wanted the lighting fixture to give a more "intense" light. Also I don't know how to make the glass-wall more "frosty". Maybe a wood ground would be nice too (anyone care to give me a cool texture?).
I'm currently experimenting with particles to create a soil and grass inside the aquarium. Further I will had some rocks (as soon as I learn how to make them), and finalize the layout with some fish...
Cheers!
Hugo Ferreira