When I started (in SF mind you), I used a 45x19 combo, then graduated to a 45x17, then to a 52x19.

Take your gear inch number and multiply by 3.14 to get an idea of actual travel distance. For instance, 52x19 combo gives about a 72 gear inch and a 226 inch development. about 18'-10" of travel per rotation.

I'd say mid 60s would be good to introduce yourself to riding fixed, and lower 70s would be a good graduation point.