I'll just add that in my experience, it's hard to anticipate in advance how a particular game is going to "age" in a small collection. It's worth thinking things through, but only up to a point. If I were you, I'd keep an eye on what's for sale in your area, and when you see something that might fit the bill, check the reviews, see what (if anything) people said about in this thread, watch a little game play video... and then if you find yourself getting excited about it, buy it!

You've gotten a lot of good advice in this thread but one that's kept coming up that I totally disagree with is BSD. You said before that you want one your wife could get into, that has modes you can progress through, and I think you said you don't consider yourself a very skilled player at this point. There are plenty of games that would fit that bill perfectly, including almost all the ones that are getting multiple recommendations here, but BSD ain't one of 'em. Now don't get me wrong, BSD is one of my all time favorites- owning one is probably the most fun I've ever had with a pinball machine, honestly. But the reason it's beloved is that it's uniquely challenging and brutal, and it stands out from almost any other game. Goddamnit I want to go down and play it right now, but my mother is visiting and the guest room is in the basement!

I don't play golf, but I imagine it's sort of like playing at one of the hardest golf courses in the world. If you're a decent golfer whose played tons of courses over the years, I would imagine playing a course like would be a special, memorable thrill. But if you're more of novice player whose only played a few courses, you'd probably have more fun on just about any other course instead.

That's not to say you should rule out a game just because the shots are tough, but BSD in another league.