MP3 saving tips from the experts.

This is probably a very basic question for the experts, but I dont know the answer.
I have many music and bodybuilding vids in mp3 format and .mov format and was wondering how I can save them to a disk. My hardrive is almost filled up and the pc is running slow, so its time to get rid of them.
I greatly appreciate any info you guys may provide.

If your technically inclined, add another harddrive. If not, burn them on a DvD.

Whats a good DVD burner to get? Will I be able to install a burner while my hardrive is maxed out?