I have 4 at the moment, but in having 4 I realize I can only fit 3. Also I'm a little uncomfortable having so much money tied up in these games. Makes me nervous if all of a sudden they decided to disintegrate into nothing.
2 are long term keepers as of right now. I have had both over a year and don't see them going anywhere soon:
GoT Pro
Met Pro
2 are good games that I like, but looking to move on from for one more long term keeper:
ToM
Judge Dredd