I bought a DIR-655 yesterday and am having some problems with the wireless connection.  I had an old Microsoft Wireless B router and never lost connection from any devices.
These are the components of my system - 
DIR-655 w/Firmware 1.32NA
Windows Vista Desktop - via wired connection
Windows 7 Netbook - via internal wireless n card
Canon Wireless Printer - via wireless
Wii - via wireless
Everything connects fine and I get network access from each device.  The Wii and printer seem to have a constant connection but its hard to tell since its not constantly accessing the network like my netbook is.  The netbook will work fine for a couple minutes.  Then my network will drop off the available networks list and then come back on a moment later.  It did this continually for over an hour last night.
I set the laptop to automatically connect to my network and to connect even if SSID is not being broadcast.  I also set up the laptop to WPA, AES, and put in my network key.  I tried changing all of the security settings on both the laptop and the router to see if that made a difference but it didn't seem to matter.
Here are the current settings on my router -
Wireless Radio :  Enabled
802.11 Mode : Mixed 802.11n, 802.11g and 802.11b
Channel Width : 40MHz
Channel : 1
Secondary Channel : 5
WISH : Active
Wi-Fi Protected Setup : Enabled/Configured
Guest Wi-Fi Protected Setup : Enabled/Not Configured
Security settings : WPA2 - Personal.