Indeed, ultimately we expect HTTPS (and possibly SPDY) to replace HTTP entirely, the way SSH replaced Telnet and rsh.
The Electronic Frontiers Foundation brought out a new release, 0.9.0 of their HTTPS Everywhere extension for the Firefox web browser. It's a response to the Firesheep extension for Firefox.
The new version takes Firesheep into account. It will likely be worth installing for that alone.
However attractive the idea of dueling Firefox addons may be, the real, long term solution is for web sites to implement complete, end-to-end TLS/SSL. Web developers please see how the EFF thinks it should be done.