FOUND A FIX!
Hey. Updated my iOS this morning on my 5 and iPad 3 and had the same stupid problem of not being able to connect to ANY wi-fi router. After trying most of the basic fixes (reset, backup/restore, router reset, etc.) nothing worked.
Got an idea and instead of the phone/ipad connecting to the router, I went into the router and added both devices' MAC addresses to the router's whitelist. This helped the router pre-identify my device and let me through as soon as I typed my WPA2/TKIP password in. On both my idevices, I tapped the > icon next to my wi-fi connection and switched the HTTP proxy to auto. WORKED!
So here's a simple step by step process:
Open router menu (usually 192.168.1.1 or 0.1) in your pc/laptop browser
Go into your configuration menu and look for "MAC Address Filtering"
When you find it, go in and add your idevices' MAC address(es) to the "whitelist"
(to find your MAC address, goto settings->general->about and scroll all the way down.)
Confirm, reboot your router and try reconnecting to your wi-fi on your devices.
Also, you might be able to connect (wifi symbol will turn on, but your won't have internet access), then goto settings->wi-fi-> your connection-> and turn HTTP PROXY to AUTO. This should solve the connectivity problem.