David, Welcome to MR!
Okay first of all, are you choosing a small tank because of the size you have for it or the budget? How big is the footprint you have for the tank?
Do you have room for a sump? This will increase your total water volumn, and you'll have a place for your heater, probes, carbon, ect.
My first reef was a 15gal. Then I added a 7 gallon. Then I put them both together in a 20 gallon. I've only ever had a nano reef. I'm currently designing a 58 gallon tank- finally a move from the nanos!
So if you're responsible enough, and you'll put the time in, you could easily have a nano as your first tank.
I'll tell you the two things that I think have helped me be sucessful with my small reefs (and my hecktic schedule)
My RO/DI filter. One thing I learned was to NOT put the impurites into the tank, and you won't have to clean them out later (as algea!)
My Litermeter top off pump. It keeps my tank level exactly where I want it to be, and I don't have to worry about evaporation problems. It also helps me dose kalk.
So if you take your time, you should be able to do it right, and have a successful tank.
(BTW, If budget is holding you back, It took me almost a year to get everything together for my first tank! Take your time and buy the RIGHT thing the first time)
Brett