Well the obvious of course:
Its a constitutional and god-given right.
It deters would-be criminals from acts of violence.
It is very functional for carriers in the Texas heat.
I think the beautiful thing about OC is that it and all of it's benefits are so obvious. I think it would be prudent to include a Frequently Asked Questions of all the common anti's counter-arguments and how we address them. And of course links to this site and TXCDL.org too.