Can't sync my iPad to my iTunes account on my pc

I have tried all that. iTunes version is 10.5, iOS 5 is iPad 2 software. It goes through the motions of syncing but then I don't see my songs in iPod on the iPad. Pictures are also not visible, PDFs stored in iBooks are not visible and books stored in iBooks are visible but not accessible. All of this happened after I updated to iOS 5!

Also some times I am not able to connect to iTunes store on iPad even when network is ok! Blue dialog box pops up saying "unable to connect to iTunes store"