This is how I define this bit:

Pro = Someone who is in it for the money.  Whether they make quality or crap is not the issue.  Of course, the better the product, the better it sells, but, to me, a Pro wants to pay the bills and maybe buy some food with the money made from this kind of business.  Time on project v cost per time really does not factor into it, since the Pro is looking at the annual income and not the time card - the more time spent up front perfecting a skill would balance with the number of quality products on the market by year's end.

Hobbyist = Someone who is in it for the fun.  Again, whether they make quality or crap is not the issue, since only some of it will be seen by others.  If they sell enough stuff to pay for the hobby, good for them, but these people would think of "that much money" as something nice to get eventually but are not actively striving for that as a specific goal.

Student = Someone who is in it for the knowledge.  Once again, whether they make quality or crap is not the issue, since most of their stuff will never be seen by anyone, even family.  These people would be in it for the experience; some will become hobbyists, some will (try to) become Pros, and some will decide it is simply not their kind of thing after all and just leave.

(Insert naughty word here) = Someone who is in it for the glory.  All they make is crap and get pissy when people leave comments.  These people want to be well respected Pros, have their masterful tutorials lauded by everyone, and make more money than Billy Gates.  Too bad they never listen, do not read or watch existing how-to threads and tutorials, and generally refuse to put in the effort but demand the rewards.