Well, the problem is that you can't get connection encryption (confidentiality) without authentication. This is because, unless you authenticate with the server you wish to talk to, you can _never_ tell if there's someone in the middle snooping all your traffic (and possibly modifying it as well). It's the infamous man-in-the-middle (MITM) attack, and it's trivial to pull off if the attacker is in the right spot.
The world is heading toward two classes of certificates anyway. The price for normal certificates (for which you only need to demonstrate that you control the domain name in question) is going to continue to go down. I hope that one day you'd get your certificate for free with a domain name purchase. Extended Validation (EV) certificates, where certificate authorities actually do some work to validate an organisation behind a certificate, are going to be what you call "full-mode" certificates.
Speaking of SSL, just last week I launched a free online service where you can test the configuration of any SSL web site:
https://www.ssllabs.com/ssldb/
