I'm currently using a Brother HL-5250DN and I'm happy with it. It's ethernet, so it stays on all the time and can accept print jobs from any computer on my wired or wireless networks. It'll spool up, print, then go back into silent powersave mode. This is useful to me because it sits in my basement recording studio. I wanted a printer that I could leave on all the time instead of having to come downstairs and turn it on each time I wanted to print.

One thing about the networked printer feature of the Brother printer I've got, and I'm guessing might be the similar for some other networked printers...

In Windows, if you set the printer to be your default printer, and the printer happenst to be in powersave mode, any operations you do that try to query the printer (such as going to the print dialog box, the page setup dialog box, the print preview screen, etc.), will sit there frozen for a long time because of the network timeout, because of the printer not responding. The printer doesn't seem to want to respond to just idle queries on the network. Only an honest to got print job makes this thing wake up quickly.

I solve this problem by setting my USB inkjet printer as the default printer, and only switch printers to the networked Brother right when I'm ready to print.