From your perspective as a webmaster, any cert is as good as another one. In fact, a self-signed cert will protect the traffic as surely as a cert from a CA.
That doesn't mean your users will accept the cert. If you want the highest level of assurance and the lowest number of browser warnings about your cert, you need an Extended Validation(EV) cert which requires you to produce paper documents proving who you are. It depends on what your users demand and that will vary somewhat with customer base, but 99% of customers will be happy with any cert from a valid signing authority that verifies the cert goes with the domain (even if it doesn't verify that the domain belongs to who the Whois says it belongs to).