I tried all the possible fixes and none had any effect what so ever until I spotted one thing I'd not tried.
Changing my router settings from WEP to WPA2 under security, thinking to myself this isn't going to make a difference...... well here I am, 24 hours later with a healthy wifi connection which hasn't dropped or cut out once.
Those on WEP and still having issues, give it a go.
1- Forget your current wifi connecting in the wifi section of settings on your phone.
2- Change WEP to WPA2 security in your router settings.
3- Two finger death grip your phone (reset holding sleep and hold button until Apple logo)
4- Search available wifi and choose your wifi and enter your password.
Now ive read other posts saying they've tried this and it didn't work and others saying they are already on WPA2 settings.
All I can post is what has worked for me.
The be all and end all is that you shouldn't have to bugger about with routers if what you've used before has been okay.
The Apple strap line of "I just works..." Is now going to be changed to "It works, for some...."
I hope for Apples sake they fix this in the up and coming update as I feel a lot of users will start to talk with their feet.
As for the above workaround, I hope all that try it is that you have the same end result that I've had.
Good luck guys.