One caveat that I left out of my earlier post is the question you must ask yourself as to whether you will want to "cut" threads on whatever lathe you get, or if all you will be wanting to do is use taps and dies to thread parts. On most of the smaller hobbyist type lathes, the difference of having an adjustable ratio lead screw, or not, often just about doubles the price of the base unit.
It is most certainly a big question that you need to answer for yourself, before you make your final selection!