I quite like 'purse bags', although not ones that approach true manbagness.
Jack Spade always has fairly classic-looking bags at reasonable prices.
http://www.jackspade.com/shop/home.php?cat=351
I don't know if a leather bag is your thing, but one bag which can go from aspiring student to worker and beyond is something like the Glaser Day Bag or Flaptop, and from what I've seen of the Day Bag represents good value given the materials, practicality and workmanship involved.
http://www.glaserdesigns.com/Pages/Briefcases/DayBags/DayBagIntro.html
However, take my recommendations with a pinch of salt - I have almost as many bags as my GF, the balance only restored decisively in her favour recently as she has adopted one of mine as her own...
@RedCOMET: You know, I only pegged to this within the last few years, but I was a big briefcase (albeit usually with a shoulder sling) user for nigh on two decades - but I realised that in fact, I was using a laptop bag a lot more. And I realised it was increasingly foolish for me to spend thousands of dollars on custom briefcases when I was carrying a $200 laptop bag more often. So I switched my focus totally to laptop bags. I suspect for most professionals, the traditional briefcases are out.