Comparing WEP and WPA-PSK is rather academic, because
AFAIK they're both fine for protecting a home W-LAN. But FWIW, it is my understanding that WPA-PSK has a human factors problem - people tend to pick a plain English key. If you can capture a valid authentication packet, you can take it home and try dictionary attacks where you iterate through possible keys until you hit the right one. It's fairly slow, 100-odd attempts per second, but very effective.
If you pick a good random passphrase (of the Zj8mqS0l variety) then WPA-PSK is very good.
