Here be dragons!
Encryption on a wireless network is like a lock on a door, it doesn't keep the bad guys out, it keeps the honest people honest.
The easiest answer is that wireless is insecure PERIOD. A harder yet answer is that ALL TYPES of non-enterprise WiFi encryption can be broken in short order. The implication is that it takes longer to break WPA than WEP, which is true, usually.
All home wifi encryption can be broken, it is just a matter of the amount of time and effort the attacker is willing to put into gaining access.
With this mentality the question becomes what percentage of the people who would take the effort to try to break into my network are going to stick around long enough to break WEP but not WPA, this question I can't answer for you.
Personally, I use no encryption at home and take counter measures on the network level. If you want to get real creative you can let the world have access but make it only port 80 http and every picture is replaced with something of your choice (think evil and then do worse) and all the text becomes;
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