Picking out my lathe has been one hard decision. I would find a lathe model then pick it apart on the forums. During this time I still had not figured out what type of woodturning I wanted to do. Was I going to do spindles, bowls, pens, pepper grinders, ect... Since I am setting the shop up for this to be a hobby I will try them all at least once. Now to the different types of lathes out there.
Pen lathe is usually pretty portable and has a swing of around 2 inches. This type of lathe is very specialized since it is ideal for turning pens(hence the name pen lathe).
Mini lathe these usually have a 1/2 to 1 hp and a swing of 6 to 12 inches. Most of these lathes can only turn a spindle 16 to 20 inches long but most can have a bed extension added so you can do most anything with them.
Floor lathe are your big boys with a 1 to 3 hp motor, a 10 to 20 inch swing, and can turn a 33 to 60 inch spindle. These units weigh a lot more than the mini's and have a much more rigid tool bed for the more serious turners.
In each type of lathe you have a wide variety of lathes and features which I will talk about later on. You will have to also keep in mind to your budget. HAPPY TURNING.