I used to collect paperbacks, although my 'specialty' was Ace Doubles rather than Modern Library. Also used to collect comics (DCs from through the 10 cent cover price period, which lasted up to early '62, if I remember right). I still have the silly coin collection (U.S. only, mostly circulated stuff, but the obligatory proof sets as well). Main collecting thing now is used Danish stamps and covers (envelopes, if you aren't familiar with the term).