For someone not "in the business", it is hard to beat a 12x36" (54"bed) Atlas, preferably with quick change gear box. These lathes are American made ( similar size foreign made lathes are generally OK too), parts are available and cheaper than better known lathes, often can be found with a lot of "set up", missing set up can usually be made or "jury rigged"( gives valuable experience), the slow speed is 28 RPM, which I prefer for reaming, and it has power cross feed which is generally not found on smaller ones. The spindle bore diameter is only 3/4", which is a little disadvantage, but you can do barrel work between centers( chamber between a center and steady rest). When you are learning, this is actually an advantage because you can take it out of the lathe, try it, and put it back in at the same place). I prefer mine for barrel work, even though I have both a Clausing and South Bend. You can do very minimum milling with a milling attachment for the lathe until you find a bench top mill( Atlas or "off shore"). If you need a full size mill, you will know from the job you want to do, that the small one won't do.
Mike