Let me preface this by saying I think a big collection of games in the home is 8 or more.
I've got about 40 of my games setup in working order, 10 or so of a mates setup in the game room, another 10 to 15 in working order but they are stored. About 20 more that need varying degrees of work, and at least 5 basket cases. I've got games that you'd only want to play with white gloves on, and others that work fine but have plenty of wear and someone's initials carved in the side. I think being in Australia generally your options are far more limited when it come to condition so you can either get annoyed by it, restore the games, or ignore it. I tend to do the latter.
There have been times in the past where I've thought about cutting back to 20 keepers in mint condition, the second I do a deal comes up and I end up with more games in various states. I've recently started collecting system 11s and that is dangerous to any ambition of cutting back.
I find as long as you have the space and the resources to maintain it, a big collection is almost always better.