I'm kind of like that with my arcade video games. I have a mix of dedicated/MAME/multiboard cabs that don't get played on a regular basis. I really only get motivation to play when friends come over. Otherwise, they get very little play. I wouldn't sell them though.
Similarly when I bought Pinball Arcade for the Xbox 360. I played the crap out of it when I first bought it and now I can't remember the last time I fired it up.
I only have two pins in my collection for now but they get a fair amount of play.