ratio: 48-18 is more or less standard; frame set up: your choice, the choosing is the fun part...love every second of it (btw, there is no wrong answer...). Go for some test rides if you know anyone with the set up you are considering and pick the one you like. instinct is wonderful stuff...

if you are not sure about fixed vs free, look into an affordable flip-flop hub...nice to have the choice.

good luck and have fun!