I'm not sure your code design methodology should be the only factor affecting your language choice. If it is really OO that is the deciding factor then Python could be said to be 'more' OO at least until Perl6 arrives(?).

Not knowing much about Python you may even find other languages like Ruby or Java are even better for OO support.

Nearly all modern languages will have OO support and generally Perl and Python should both have enough OO for your needs.