Are postscript printers necessary for printing large pdfs compiled from LaTeX files?

A PostScript printer would be useful (some work is done outside your computer) only to print PostScript files, however it is not necessary. If you want to print PDF's, a PostScript printer doesn't help, however you can still print them.

See also http://desktoppub.about.com/cs/printing/a/postscriptprint.htm, especially If you are a professional desktop publisher or graphic designer who works with commercial printers and service bureaus you will probably need to know and use PostScript remark.

I had once a printer with an in-built postscript interpreter (laser printer at this time always had one). That can be useful: You can print a postscript file without going through a postscript interpreter and the printing system of your computer. I could download ps-files to the printer and the postscript interpreter there did all the work. This is faster and puts much less stress on the CPU of the PC. As at this time I had to print a lot of tournament builetins and had a not very powerful computer the time gain was very welcome.

But nowadays I don't think that it is needed, certainly not for your type of printing. I would more care for network capabilities: Make sure that you can print from more then one computer through wlan or ethernet.

PostScript -- see here: http://en.wikipedia.org/wiki/PostScript -- is a computer language. I'm not an expert for printing, but afaik if the OS doesn't support your printer, you can use it nonetheless if the printer "understands" PostScript.

For people using Microsoft Windows there will almost always be a printer driver, but for Unix, Linux and whatever, PostScript is at least a fall back solution.

Disclaimer: I'd be happier if somebody with greater knowledge of PostScript could verify this.

As some folks here have doubts about the connection to LaTeX: In the old days TeX was not able to produce a PDF, but DVI. From DVI there was a way to get a PostScript file. And pstricks can do some things Tikz never will be able to. But don't mix these three use cases of PostScript (printer "driver" / output format / drawing) of PostScript.