Heck, just start playing the Uncharted game that came with it and enjoy it. No need to keep spending money to make yourself happy. That said. I don't know if it just comes with Uncharted 3 or 1 & 2 also, but you can pick up 1 & 2 as a bundle if you like to start at the beginning of a story, they're all top-tier games.
A good casual game I really enjoy, and the only one besides Flower (which is awesome, don't let the name throw you off) I've gotten my wife to play is Zen Pinball. It's fun to play each other, and it's one that anyone can play and enjoy if guests come over. Marvel Pinball is by the same company if the Marvel themed tables are more your thing. I like both.
I would start with the incredible backlog of highly reviewed games that are more than a year old and hence cheap, rather than rushing out to spend $60 each on the new releases. Keep in mind that even some highly reviewed games might not be to your liking if it's just not the type of thing that interests you.
I don't know how old your son is, but one of the most fun experiences we had on the PS3 was playing through the original Resistance in co-op mode. You get to cover each other and work together through the whole storyline. There's definitely violence, shooting aliens and such with a gritty realism style of graphics, but I think the language is kept in check since it's set in a 1940's alternate history.
SuperStardust was a good choice for the 3D. It looks awesome. It does get my eyes tired, but I think it's just because it's so intense that I don't blink