I have a new connection with a nice new router/cable-modem. I'd like to setup it up optimally and needs some pointers. I am a complete n00b when it comes to routing.

I want to end up with two separate subnets, 10.1.2.0/24 and 192.168.1.0/24 each available on their own wireless channel/SSID. Both firewalled. I want my wired computers on the gigabit switch, optimally with public ips. I want to be able to reach 192.168.1.0/24 from 10.1.2.0/24, but not vice versa. Everyone should have internet access.

Hardware and capabilities:

Netgear CG3100. Handles cable connection. Gigabit switch. 802.11n. Can do DHCP, firewall, NAT etc. Can choose subnet. Can turn of NAT and if so hand out up to 4 public ips. Somewhat challenged when it comes to configuration.

WRT-router. Runs DD/Open-WRT very stable. 100 Mbit switch. 802.11.g Can do DHCP, firewall, NAT etc. Can choose subnet. Highly configurable.

I hope to be able to keep 10.1.2.0/24 on the CG3100, for speed reasons and 192.168.0.0/24 on the WRT-router for quota and user control reasons. On my 10.1.2.0/24 network I plan on running servers for various services.

Should I turn of NAT on the WRT-router? Or on the cable modem? Activate what in that case? Is double NAT always f-ed up?