Last night I bought:
To The Moon
Thomas Was Alone
Psychonauts
Braid
So far, these have all been worth the money.
Thomas Was Alone has little replayability, but it has delightfully witty British commentary (maybe it's Jonesy?
) and is thoroughly enjoyable (even if you find it confusing how you'll emotionally connect with various rectangles) for the $2.49 I spent on it.
If you want an emotionally engaging game that takes you on a story about reliving one old man's past to fulfill his dream with him,
To The Moon is exactly that. I'm only 30 minutes in and I just want to know more about what's going on in this man's peculiar life.
Psychonauts and Braid are famous enough that I won't bother with a summary (unless you'd really like one!)
BMO