As part of CNET's"spring cleaning" the published a decent article on organizing your music collection physical or digital.
In addition the four big streaming music services can also double as a music "backup" for your collection. Where Google Play Music will hold 25,000 songs for free. Amazon Prime will hold up to 250,000 & iTunes will hold your entire collection for $25/year. Also OneDrive has finally stepped up to plate, letting users stream music stored on their drive. But users can only do this using a Xbox or Win 8.1 device.