I am very happy with my D-Link DNS320.
Very quiet in operation, very simple to set up with a straightforward web interface. I have never needed to adjust the default settings which send it to sleep after 5 minutes of inactivity. Wakes within a couple of seconds on demand - certainly fast enough for it not to be annoying.
Supports NFS, SMB and DLNA/UPnP
Works with everything I have in the house - XP PCs, Windows 7 PCs, and various android boxes/phones/tablets. I'm sure it would talk to my Humax HDR-Fox T2 if I needed it to. My daughter was here over Xmas and was delighted to be able to play movies on her ipad.
It is the only storage device that works reliably over Wi-Fi with the AC Ryan PlayOn media player I have in the bedroom (via NFS).
I've tested it with three different devices streaming different movies simultaneously, over LAN and Wi-Fi and it didn't miss a beat.
....oh, and it has on on/off switch on the front