HP have the market cornered
And for very good reason too.
The HP lasers you find in offices are real workhorses, they can take a hell of a beating.
Get one of their entry level business models and you should be set for life.
The only other safe bet I would suggest other than HP would be Xerox.
Those are really the only two brands you should be looking at for laser printing (black or colour).
A sheet feeder for scanning would be nice
You tend not to find multifunction laser printers, and when you do, they're as crap as the multifunction inkjet printers. Don't waste your time or money on them.