On the World vs SMB3 debate, I definitely fall on the side of SMB3. More and shorter levels with a wider variety, even if there is no Yoshi.

I really feel like we got the better deal with Super Mario Bros USA (as they called it when they re-imported it back to Japan). Lost Levels is sadistically unfun (congrats on beating it! That's a real accomplishment), but SMB2 is a neat change and a great game in its own right.