I've only ever put cream cheese on them.
That's just what I've always done.
I once knew a girl who put peanut butter AND chocolate spread on her bagels, which is just mental. I wouldn't even ruin toast with that nonsense.
anyway, since you're here, here's a bagel-themed clip for your perusal: http://www.youtube.com/watch?v=NEZGYpd7cPg
Britta's the worst.