"You belong here" is okay, but for me it's a bit too mushy and doesn't say anything about what the city is all about.
It almost sounds like it's speaking to immigrants, not tourists. Is that what we want?
I like "Expect the world" as an Olympic slogan, but it's not quite right for the city itself, I think. It's on the right track though. It might grow on me. Expect World Class? Just kidding.
I know I haven't offered an alternative here. I once suggested "Come see what a city can be" but it was shot down on this or another forum. I don't like it that much either anymore, but at least it's not nothing.