It seems Ubuntu Gutsy's NetworkManager is erratic, didn't have a similar problem in Feisty. I need to restart after resume often now. Just to save me the hassle of typing and my wife having not to deal with it I added a resume script on /etc/acpi/resume.d called 99-restart-wireless.sh that contained:
#!/bin/sh
/etc/dbus-1/event.d/25NetworkManager restart
--edit
The above is lame. I figured the problem, I needed to unload the broadcom drivers of the dv6000 during suspend. Just edit /etc/default/acpi-support
MODULES="bcm43xx"
That should unload bcm43xx module during suspend
