If you haven't already... go to Settings-->Reset-->Reset Network Settings. Then rejoin your WiFi network and see if it helps. It seems to have cured my issue.
Though I don't think I had the problem nearly as bad as you and others do. In my case it would seem to drop Internet access (yet still be connected to WiFi) but not every minute... only if I didn't use iPad for awhile (30+ minutes).
I was having the exact same problem as you, it would work then stop and then if I left the iPad alone, it would start working again. So I tried to reset network settings but that didn't work, the app store wouldn't even open. In my case it seems like the app store makes the wifi stop the fastest.