I personally like the O-H I-O Chant.
Living in a different state and hearing O-H! called out while walking down the street with friends is exciting and fun. My friends are always amazed at how many Buckeyes travel out west. It brings strangers together for a brief moment. I guess living in Ohio would make it annoying, but I certainly hope people don't stop doing it to me.
PS- Especially hearing it while on top of a 14,000 foot mountain top makes it even more special.