There's no file compatibility issue, but you might notice issues with album artwork which would either missing, different or the same as iTunes normally won't store the artwork as part of the file. Also, if you ripped your music to mp3, acc, alac or aiff, the tagging will be preserved, but with wav files you will lose the tagging information (title, track, artist, etc).
If do have "wav" files or concerned about your album art, then another option is to enable home share on both the PC and the MAC and have it "sync" the files over to your new mac. If you plan on using an external drive for the music, make sure you point the itunes library to that before you copy over.
Don't forget to get an additional external drive for Time Machine backups. You should size the drive to be larger than your internal drive and external drives that you want backed up. i.e. You have a total of 500GB of internal and external drive same that you want backed up, I would get a 750GB or 1TB external drive for back.
