S.W.
EVERYONE has an opinion about names or has an association... but since you're asking, given you aren't asking about Maxwell, Maximillion, Leopold, Leon, Leonard you must be thinking of just the above shorter verisons.
Max: I really like the name. It's strong. However, I dated one so I couldn't do it, and in my daughter's school there are two in the same class, so for me it's too popular. If you're cool with the popularity, then I like this name the best.
Leo: That's my sign in the Zodiac (although I don't really follow such). There's a children's television show "Calliou" and he's a whiney kid. His best friend is Leo.
Noah: Good friend's nearly named thier child Noah, until they the started joiking around, "do you know - a [fill in the blank]". Kinda silly, but they ended up naming their little boy Eli (Elijah).