29 gl (nano?)

[DanG]

A bigger tank is always nicer from the stand point that if you have a chemistry change it takes longer to become a big issue in a larger tank compared to a smaller tank.
If you went with a smaller one now and went bigger later, you'd probably need new lights, if you bought a bigger skimmer now, you could use it on either tank, same with a bigger heater, but it's safer to run 2 smaller heaters on a bigger tank because if one malfunctions, you're not completly screwed.