I've not really seen many negative two gallon tanks... so I'll be honest.
If you're looking for a small footprint and the surface can hold up a five gallon's weight go for a marineland hex-5. They include filter and light, all you have to add is heater and they're $38.00 before tax at petco for yellow-card-carrying-people. Kinda hard to beat deal and the small footprint and exceptional engineering is very nice.
Many people like the three gallon round tank as well and there's a cute trick you can do with it. Leave the whole under-gravel system in place and buy a round sponge that will fit over the lift-pipe, just stick that sponge on the top of it so it sticks up above the water line and it'll work as a filter - very very easy to take off and quick-clean in a quart of freshly Prime'd water. You can also buy and use Whisper 3i filters in the three gallon round tanks.
Do NOT get the Marineland Eclipse three gallon OR the "Glow Fish" three gallon. The marineland 3 has too hot a light (87° peaks) and the "glow fish" (from tetra) has soft acrylic which is easy to etch with algae.
The 2.5g minibow are nice reliable tanks, the included filter is very unpleasant for betta so I agree with MiB's not using it. Thats one of the tanks where a Whisper 3i would do great.
Last edited by Thunderloon; 12-17-2011 at 06:57 PM.