OKI C3300-N
Got one of these about 6months ago and it rocks. Don't do real heavy colour printing, but is fairly quick, is network enabled (i wanted that for wireless printing) and duplex ready apparently. Well in your budget.
Bought it from these punters -
http://www.shopoki.co.uk/acatalog/c3300.html (aka printerland.co.uk)
Depends on what you want it for i guess.