I'm still using a NeXT 400DPI Laser printer from 1990. The upside is that it's a software printer, so you get a NeXT Station/Cube as a print server.

Edit: It uses a Canon-SX engine and HP 95A cartridges - same as HP laser jet II/III and Apple laserwriter II. So parts and consumables are easily available.

Obviously the HP laser jets and apple laserwriters with network cards in them are also excellent choices.