Longevity, Dell. You can find something at every price point.
You still want a modicum of performance, and horsepower for dollar, either Lenovo (formerly IBM Thinkpads) or HP wins there. HP at the lower price points, Lenovo at the higher ones.
Stay away from names you don't know or aren't mainstream; you'll get the junk you pay for.
You can find EXCELLENT examples of 1-2 year (or generation) old versions of kick-ass models for fractions of new prices. If you just want a print server, I'd buy used, try to snag a Dell or Lenovo already equipped with an SSD because print serving is 99% about file access, and the rest is all network access. CPU load is pretty low.