My DWA-160 RevB works great with my DIR-825, DIR-665, DIR-655 with Win 7 and XP on both bands.
The secret, which only works with RevB of DWA-160, is to:
1) Uninstall Dlink DWA-160 drivers and software.
2) Download the latest USB Ralink drivers and installation application from www.ralinktech.com/support.php . It supports Windows 2000, XP 32/64, Vista 32/64, Win7 32/64. At this writing date is 12/31/2010.
3) Run downloaded .exe file. Select to "Install drivers and Ralink WLAN utility". After installation run WLAN Utility and read the help. I found little about this utility intuitive but it works great.