Man, there are some awesome tanks in this thread!! Here's the tank I've had for the past year, a 5.5 gallon that is only inhabited by my unnamed male CT.
Really want to try experimenting with soil or sand soon, especially in my 10 gallon!
Tanks at home: 5.5 gallon with a male CT betta, 10 gallon with 4 females and an ottocinclus, and a 1.5 gallon hospital tank.
Work tanks: a 1.5 gallon with Nemo, a male VT betta; 2.5 gallon with Blue, a male VT; a 2.5 gallon with a rosy faced barb; a 5 gallon with 2 cherry barbs and a rosy barb; a 10 gallon with fancy guppies; and a 10 gallon with 5 silver dollar tetras!