Is WEP sufficient to block inadvertant access by neighbors? Yes.
Is it sufficient to protect your network from the bored 13 year old next door? No.
WEP is breakable with simple software. The last time I checked, about 5 years ago, it would take about 15 minutes of sniffing to have enough data to crack 40-bit WEP, and on the order of a couple of hours for 128-bit WEP.
But WPA isn't a perfect solution, either. Scan down this page to see the most recent articles on WPA security breaches discussed at Slashdot :
http://slashdot.org/search.pl?query=wpa
If there is a possibility of a nearby bored teenager, I recommend turning off the Access Point in your router, then have one of your wired platforms run OpenBSD, and insert an OpenBSD-supported access point via USB or PCI, or an ethernet-connected AP via a 2nd NIC. Have this OpenBSD platform be your WiFi router, inside your wired network. e.g.:
Code:
{internet} -- [ISP's router, no AP] -- {wired LAN} -- [OpenBSD router with AP] -- {WiFi}
Other options require trusting in WPA, and, either obtaining a WPA-compliant WiFi NIC for your laptop, or, using your existing ath(4) NIC with a different OS in the laptop that has a WPA-capable driver.