It sounds like you might have changed the permissions of your ~/.ssh directory and/or your ~/.ssh/authorized_keys file. Or possibly made your home dir group or world writable.
~/.ssh should be 700 (drwx------) and ~/.ssh/authorized_keys should be 600 (-rw-------).
Your private key file(s) in ~/.ssh (
id_dsa, etc) should also be 600. The perms on the public key files (
id_dsa.pub, etc) are less strict - they can be world-readable.
All these files and directories should be owned by your user.
If your home directory is world-writable and StrictModes is set in sshd_config (default is "yes"), then sshd will not trust anything underneath your home directory (including ~/.ssh and everything in it) because a world-writable hoome dir means any user on the system could have created or modified the files.
I'm not sure how sshd on Centos handles group-writable home dirs, but the same may apply if your home dir is group-writable - any user in the group may have created/altered the ~/.ssh files. (IIRC Debian's sshd is configured to allow group-writable home dirs because Debian's adduser traditionally creates a group for each user which only the user is a member of)