Piece of paper doesn't mean shit.  No art job will turn you down just because you didn't go to school, if you've got awesome work.  If you have a piece of paper and a portfolio thats just "ok", things are iffy and that paper really isn't helping you any.  Art jobs care more about your art.  An art degree probably WOULD help you get a government art job though.  They care for some reason.  (This is for the U.S.A)

As for portfolios, I've been told put your best works first and last, but don't have any work that isn't awesome.  heh.  I think you could go as low as 10 pieces if they're all good.  Better to have 10 good ones than to throw in 2 crappy pieces to meet the commonly stated 12 - 16 requirement.  I wouldn't do much talking if any.  Let them do the talking.

I didn't feel that I had enough good stuff for my portfolio when I was applying to college.  So I did the other option they gave, to do 6 or so assignments they listed.  Did them in a week, turned in portfolio, and got in.  You have to be really shitty to fail an incoming freshman review I think.  I had no clue about the world of illustration or painting or anything.  I hadn't seen all the awesome stuff I've seen now online.  I was blind.  But I loved to draw since as long as I can remember and had some chops.  And honestly, so many people go into art school that probably hardly ever drew, and never seemed to work on anything while they were in art school. 

Some of those people didn't pass the freshman to sophomore portfolio review, but still many did pass that had lousy work, even all the way through graduation.  I can't fathom how people could fail the first year though.  I had to put my incoming sophomore portfolio together in 3 months instead of 6 or 7 or whatever everyone else had, since I started school late, and I got into the department I wanted (illustration) anyway, no problem.  They let me in and let me make up the classes I missed over the summer.  Schools are businesses, they aren't going to judge very harshly.  If they did they wouldn't make as much money.

But don't relax because of that.  The work place WILL judge harshly.  Myself as well as most of my fellow ex-classmates can't get art jobs.  yay.  Some of us do a little freelance but nothing thats paying the bills.  A lot are working retail and shit.  $8 an hour to put up with the stupidest people on earth.  I could have worked harder.  I should have.  And I was by no means one of the super slackers.  I don't think I ever missed an assignment.  Hardly missed any days of classes.  But just meeting the requirements of school won't get you very far.  I see that now.  You gotta keep busy with personal work.  And do more than one finished piece for assignments if you can.  School didn't tell me what to do, how to get better.  They just dished out assignments.  Which actually tends to make you fall back on what you already know (which is probably WRONG cause you're young).  Ugh.

As for the "is school worth it?" discussion.... I'm a bit bitter about my education.  I don't feel I learned much.  I feel I have learned more from books, forums, and exploration.  And just plain old learning to see better.  Analyzing.  But I think I may not give school enough credit.  I was exposed to things I probably would otherwise have not been.   I remember in the beginning teachers constantly telling us to loosen up.  I draw very differently now than when I first entered school.  (though I still think I'm too tight and too much of a pussy).  And though I feel that school was overall just an endless parade of mindless assignments with very little in the way of goals and teaching and useful critique, there were a couple great teachers that have certainly sculpted me.  There are also a couple of great students that have provided some friendly competition.