I use a Canon MP970, about a year old but probably superseded by now. It connects directly to my router so any computer on the local network can use it. It scans, prints on CDs (you need the printable type of CD) and prints duplex (both sides of the page).

When I bought it I tried to do some analysis of the running costs and pretty much failed.

The duplex option is the one I've found most useful, although I didn't buy the printer because it had it.