Hi, sorry to ask again...

Can anyone give me some advice on gear ratios?? I'm getting my first singlespeed freewheel custom built, and have been asked what gear ratio I want. The standard he (the guy that's building it) uses is apparently 52T 18T. In one of the threads, it seemed like most people were going with 48/16 or 17. is this wildly different, and if so, how?

I have read the other threads about gear ratios and am still confused! Sheldon Brown's calculator was fine til it got to the "chainrings" bit.

This will be my first commuting bike, my heart's set on a singlespeed, but I didn't realise it could be so complicated.

If it's any use, I'm 5'4", female and only moderately fit. Cheers muchly.