I've sold all my bikes bar the Pro-Star, and who's to say that won't go either if I feel the need. One thing that can't be sold is memories and knowledge, the rest are just materials related to it.
The negative side, all the money has gone into a new Kitchen so I'm just glad I bought a couple of toys beforehand.
I have absolutely no regrets with anything I've sold and was totally sure about that, if you're not then don't.