I loved my eeePC back in college - either a 700 or 701 running, I think, Xunbuntu. Perfect for taking notes in class, which a tablet, or even the Surface RT I have now, would be garbage for. Not bad for light hacking either.
I still have two of the original eeePC machines, which I use to run antique Teletype machines. The Linux version is crappy. The WiFi connection system gets hung up if anything at all goes wrong, and the "union" file system leaks inodes, which have to be cleaned up with a script every few weeks of use.
You can get a tablet for $39, which is useful for little dedicated applications.
Still, I could buy 3-4 of my old eeePCs for the price of a Mac Air, and neither is really in the same form-factor. When you're working an $8/hour work-study job for your discretionary income, that price differential matters. The eee was also great for fitting on those comically tiny lecture hall chair-desk surfaces that a 10-13 inch laptop would swallow up, with room to spare for a honking big container of bad, strong coffee.
They would also fit on an economy-seat airline seat, and I didn't have to worry about the douche (no offense) in front of me breaking it by slamming his seat into recline mode. Was awesome.
Still, that's a pretty small niche.