The next few weeks I'll be busy but I already found a game database and I'm collecting (damn) all the information you're giving me.
Up to now, the primary need is avoiding buying duplicates, followed by metadata (where it was bought, how much was paid, variation specific info) and then collection value.
Maybe, I'll add a ordering generator: it will suggest how you should order them in your shelf, by title, year, publisher, genre and so on. In my mind it would be awesome
The most difficult would be fcgamer's use case but I think it's doable.