Laptop and RPi both need internet access from the home router (192.168.1.1) via WiFi.
I have my RPi connected to my laptop with an ethernet crossover cable for faster file sharing.

The following config makes my RPi get no internet when the ethernet interface is on:

RPi:    wireless:   ip: 192.168.1.129 (needs to be static for ssh and other stuff)
                    subnet Mask: 255.255.255.0
                    default Gateway: 192.168.1.1

        wired:      ip: 10.0.0.1
                    subnet mask: 255.255.255.0

laptop: wired:      ip: 10.0.0.2
                    subnet mask: 255.255.255.0
                    default gateway: 10.0.0.1
                    "Only use for resouces on this connection": [✓]

        wireless:   automatic