said by Balla :
I have the same Linksys 3000 install behind the ubee. I left the Ubee in NAT mode like when they installed it. The linksys needs to be set for dhcp and the linksys WAN should be plugged into a port on the Ubee. So my linksys WAN grabbed a 192.168.0.3 external address. And interally (through linksys wireless) its handing out 192.168.1.x addresses. On the Ubee I then made 192.168.0.3(WAN IP for Linksys) in the dmz so it will pass traffic to it. Or you can port forward all ports to the 192.168.0.3.
This has worked well for me so far besides having a pc plugged into the Ubee switch and not being able to the the 192.168.1.x network. But through the linksys you can access both 192.168.1.x and 192.168.0.x networks.
I agree with CptGemini and have had personal experience with this.
I did exactly as you are saying but had a TON of issues/latency while browsing the web whether directly plugged into the LAN or on WIFI. It seemed like there were dropped packets or DNS resolution was really slowed. Speedtest.net still reported great speeds and I was fine while downloading a file but browsing the web was horrible. I entered DNS directly into my TCP/IP settings but it made no difference.
I then went to bridge mode and everything works perfect now and web pages load instantaneous.