Even just MAC address restriction should stop most poaching without the need for WEP encryption.
Was over at the company HQ just before Christmas. I've been asking them for ages to sort out a W-LAN access point, so when the wireless caption came up on my laptop, I had a useful few hours being able to research stuff for one of our projects. "Thanks for getting the W-LAN sorted", I said.
"Ve havn't - must be ze guys upstairs!"
Oops!