My dad sold mine when I was a kid, in order to get me a PC XT clone. It was a good decision -- the PC was a much more capable computer and I learned how to program with GW-BASIC -- but I really wish I still had my C64.
While working with emulators such as VICE is great, it's not the same as having the good ole breadbin :(
C64 has a special place in my heart, and I will never forgive myself for selling mine. It was the mid 90's and I had just gotten a shiny new 486.