ASk HN the case for going all OpenID Vs. local accounts Vs. Both

We are implementing a user system and wanted to base it entirely off OpenID. We will store some account details, but use OpenID for all authentication and such. We were curious how much pushback we will get from people that don't have OpenID or like have separate accounts for various things. Who want to sign up and make a password on our system. Should we allow both? Anyone with experience with either case?