"One thing to note about the use of WPA is that it greatly reduces the ability of people to eavesdrop on your wireless conversations. In security terms, it means the integrity of your wireless packets is protected."
It's extremely important to remember that packets are only protected on the wireless network - once they head onto the general internet they're completely insecure again. If you're entering anything you wouldn't want to become public you should be using SSL, SSH or another protocol with strong encryption. As a bonus, your wireless network setup becomes much easier since you can treat it just like the internet.