JAWUG

Airopeek - http://www.wildpackets.com/products/airopeek/airopeek_nx/overview

For Fee - Windows - No weak key detection - Cloaked SSID detection(?)
If you want to pay use Airopeek NX

Netstumbler - http://www.netstumbler.com/downloads/

For Free - Windows - No Weak key detection - GPS - No cloaked SSID detection
If you don't want to pay - Netstumbler is a great alternative if you like soothing out of tune piano sounds - be sure to use Airopeeks drivers since MANY WLAN cards default drivers only report signal and not SNR. If you only get green bars with no red bits at the bottom or the red bits don't change size, you have this problem. Also alot of drivers do not "let go" of SSIDs even when they are out of range. Again get the Airopeek drivers to fix this.

Kismet - Homepage : http://www.kismetwireless.net/

For Free - Linux - Weak key detection - Cloaked SSID detection - GPS - Intruder Detection - Lots More. It even runs on openwrt as a drone - http://toys.lerdorf.com/archives/20-Kismet-on-the-Linksys-WRT54G.html
The best howto on build and get Kismet working with all its bells and whistles. A bit old but is still valid - http://www.tipsybottle.com/technology/wireless/RedHat8-Kismet-HOWTO.shtml