I have a secondary ntfs hard drive in my current build on which I store music, games, etc.
If I install a new OS on my primary C: drive (moving from 32bit 7 to 64bit 7 pro), will it still recognize the secondary drive and files therein?
Yes. Recognising a drive (and it's contents) in 64-bit Windows that was previously used in 32-bit Windows is not a problem.
The only scenario in which you would have a problem is if the secondary drive had an NTFS partition (which it has), and you were trying to access it's contents from Windows installed on a FAT32 partition.
The potential for that problem to arise is fast disappearing as Windows on a FAT32 partition becomes ever more rare.