Even though Super Paper Mario wasn't as good as either of the two previous games in the series, it was still great. Tons of lol-worthy moments, particularly chapter 3. The only real complaints I have with the game are pretty minor, like having to switch to Mario all the time just to flip dimensions. Still, it's a fun game, and definitely deserved more love than it got, even if the floating around in space parts of chapter 4 were really lame.
If point and click puzzles are something you like, or think you might, Zack and Wiki is freaking amazing. I think you can get it for like 10 bucks now, so yeah, definitely worth it.
I had some fun with Elebits when it first came out. Definitely not worth the full price I paid for it, but assuming you can get it on the cheap now you might want to consider it. The concept of the game is very simple but still pretty fun, and if nothing else the soundtrack is really quite nice.