It's a question for OSX & Windows 7 users who jump between one system to another.
I'm on Windows now, and I've got this music folder in my main hard drive. I'm planning to buy a Mackbook Pro soon and I need to share this folder (along with Pictures and Documents but that's something easy to do), and maybe an external HD or a network solution.
On OSX i would use iTunes, and its library system is problematic for sharing.
On Windows i use MusicBee, a simple music app that constantly watches a folder for changes.