Needing SSL Certificates - Who is the best?

[tntgentoo]

I am looking for a set of 128 bit certificates for my web sites - does anyone have experience with the current market? I am looking at Thawte and GeoTrust. Some web sites say GeoTrust does not support older browsers.

Secondly, what about popd-ssl? What kind of cert to you need for THAT?

I have my mail system set up with self signed certs - which prompt the user to hit OK. I am just wondering what kind of cert to get for the email system (postfix / cyrus-sasl / courier)

Thanks,
TNTGENTOO