First off, what do you ultimately want to keep? What are your goals? Start setting up for your goal rather than figuring you'll upgrade later on; you'll spend less money that way.
A fuge isn't required but it can be nice if only to give you space to grow macroalgae to harvest for nutrient export.
Is there any way for you to incorporate an overflow and sump?
I used to run a 29 gallon reef, and if I had to do it again I'd definitely get the tank drilled. The siphon overflow was the most problematic thing about it.
http://reefkeeping.com/issues/2003-05/totm/index.php
Ken