I simply burn most of my audio, picture and document files onto CDs, then delete them from the hard drive. I downloaded a freebie program called Visual CD that enables me to index the CDs that I burn, so if I'm looking for anything I need only search the index to find which of my 50-odd CDs it is stored on.

This method has the added advantage that I can take the CDs anywhere.

At the last count I think I had 19,000 files on CDs.