I've bought a Xerox Workcentre 6505 Colour laser all-in-one printer last year. It supports USB and ethernet (but no wifi). It's got a duplex module which works pretty good. The paper doesn't curl at all.

I'm not a heavy printer user, so I'm still using my first set of toners. The paper has never jammed on me yet.

I'm very, very , very happy with this printer. It replaced a HP inkjet all-in-one which had annoyed me for quite some time (slow, large ink consummation etc). I bought it via one of those "daily deals" kind of things (after doing some research on it), but I haven't regretted it for one second. In fact, this may be one of the best peripherals I've ever bought. I even find the photo printing quality to be very good. Some say an inkjet will do a much better job at this, but then I wonder how much better this can get? It sure lives up to my demands.