Verified answer

Well, I like 3 best of all, but it's a matter of taste.

Mario 1 is a classic. Mario 2 is kind of ... different. In fact, it originally wasn't a Mario game. It was a DIFFERENT game, but they replaced the characters with Mario, Luigi, Toad & Peach. It's interesting too, but quite different.

Depends upon what you want. If you want the classic fun game that started it all, go with the first. The second is a bit iffy, but it is still fun. As was already said, it was a different game, Doki Doki Panic, but Nintendo went and changed it to Mario and co. But the third is also one to think on, as it is as critically acclaimed as the first. Plus there is so much new stuff added.

So really, it's all a matter of opinion. Truthfully, I'd go with Super Mario Bros.

Super Mario Bros. 3 comes in a very close second, though.