My take on tanks less that 20 gallons is that you should really have livestock in mind that you want to keep in a small tank for a while. It isn't so much the water quality concerns (assuming the tank owner is committed to doing the necessary maintenance) as much as the cost to setup not one but two tanks should you decide that you want to uprade after a couple of months. Chances are you are looking at buying more (or larger) pumps, filters/skimmers and lighting at a minimum if you get bored with the 10-gallon. Essentially you're buying equipment twice over a fairly short period of time. As RNeiswander mentioned you are also limited on livestock choices and the overall number of anmials you can keep in these size tanks is also limited. You mentioned this being a FOWLR and unless you go with micro sized fish, your looking at 1 to 2 fish total. Also, clownfish are not good fish for a 10-gallon if that is what you are considering.
None of this means that you can't have a great looking 10-gallon tank. You could load it up with inverts like sexy shrimp and maxi-mini carpet nems which really looks stunning IMO. If you stick with the 10 gallon, keep it simple and use it as a test for whether you want to stick with the hobby. Good water, good rock, good flow and a heater is all you need. I would suggest adding at least a HOB filter like an Aquaclear 50 or 70 (or even a 110) to run some mechanical filtration (will need to be cleaned or replaced often) and some carbon and/or GFO. The trick to using these filter is to keep them clean so that detrtius doen't collect.