I had this same issue. I would go to my updates screen on the app store on my iPad 1 and it would just display a blank grey screen (where normally if there were no updates it would say "All Apps Are Up to Date"). I tried restoring a few times and it seemed to work until I synced my apps again. I tried adding my apps a few at a time (10 or so) until I found the specific app that was causing the problem (in my case it was the Philadelphia Inquirer). When I removed that app from my iPad, I was able to get my update screen to work properly again.
Any apps that you remove from your iPad may cause data to be lost, so I'd recommend backing up before doing any restore to try and troubleshoot what app is causing the issue.