Some songs won t sync from iTunes to iPhone

Ok, so I have had the 4S for some time now, and I am really beginning to be frustrated with the fact I can't sync all of my music. It's almost as if anything I purchased prior to getting the 4s (had 3GS prior) will not transfer over. I have tried syncing all music, removing everything, restoring, and nothing works. iTunes allows me to play the music, and it syncs fine with my iPod with no issues. No matter what I try about 200 of the 500 songs I am trying to sync are actually on my iPohone, yet all of them are on the iPod just fine. I have plenty of room on the iPhone, and I receive no errors (even reset warnings just in case it was something I previously shut off) when trying to sync to indicate they won't be there. In fact the "Capacity" bar shows the space it should take up, then after I sync and go back the space is cut in half.

No one has been able to help, can anyone please help! The songs its deciding not to include are some of my favorite...to the point I bought two of them a second time