Same issue here.
iphone 4s with ios 7, itunes 11 last version. Windows 7 64bit and MacBook Pro (makes no difference).
At first I do all the mentioned and suggested things to avoid incorrect syncing but nothing could fix the problem.
I wrecked my whole iphone (re-installing, resettings etc.) with this bug because I cannot snyc my music correctly. Unbelievable.
I found the hint in this forum that you don't have to activate wifi or mobile data and also no backup in icloud as well because the problem seems to be that if one sync the device something happened arkwarked between apple server (icloud) (maybe depending on purchased tracks) so the sync is going to nirvana with "wating for ...." with an endless rotating syncing symbol on the device and in ituens as well.
After 7 resets and reinstallations and all the loss of my synced music on the phone (more than 10k music) I am really p... o...
The way of syncing seems to be changed in ios7 and itunes 11 because after the message "copying tracks" you get the message "waiting for ..." but nithing is happened.
My experience until now:
You have to change basically the Backup to Computer (NOT to icloud) and disconnect the device from inet (wifi, mobile data) before you want to sync music. After this you can apparently sync correctly.
You can check if itunes is copying the tracks when you have a look on your device under "settings" ... " info". The amount of tracks should change every few minutes (about 6 tracks per minute if you have changed the settings to 128bit like I do)
BUT if you forget to deactivate wifi and mobile data next time before syncing you will get the mess again and the system will hang again.
It is so bad and I am thinking first time about getting rid of apple products :-(