I'm struggling with this at the moment - I really want an Elvira or a JP2, but I am out of room (and cash) so something has to go. HOWEVER- every time I pick one, I'll play a game on it, realize I actually still love it and change my mind. I've never thought any of my games would be bolted to the floor, but I think i've just created a small collection now that really do click with me, and I've developed somewhat of an attachment to them.
Probably this is exactly why people's collections keep growing after they promised themselves (or maybe there better halves) they'd "just get one"... yea right...