Personally I'm hopeful that Firesheep will be what it takes to persuade browser vendors (and the HTML5 crowd) that real usable support for HTML login forms based on HTTP digest authentication is a necessity.
There are some pretty significant issues involved in rolling out full-on SSL which while not insurmountable do lead one to wonder if a more lightweight solution like HTTP digest auth might be sufficient for most non-security-critical cases.
On this topic http://www.cgisecurity.com/2010/01/weaning-the-web-off-of-se...
is worth a read.
2. As a pragmatic matter, it seems more likely that Microsoft would update the various versions of Internet Explorer on Windows XP to support SNI, than that all web browsers (including Internet Explorer on Windows XP) would be updated to support HTTP digest auth with a customisable UI.
Having said that, I'm in favour of web browsers supporting both technologies.
If any of your users are using Internet Explorer on Windows XP, then this seems to still be true, alas - http://www.alexanderkiel.net/2008/04/22/status-of-tls-sni/
This isn't an issue for the likes of Facebook, of course, but it is a problem for sites small enough to be on shared hosting.
Clearly they're not all running Internet Explorer, but equally clearly it's far too early to lock out clients that lack SNI.
http://en.wikipedia.org/wiki/Server_Name_Indication#Support
That is unfortunately an issue that only Microsoft can rectify unless developers on the Windows platform want to take the time and effort to re-implement parts of the SChannel API.
Someone could sniff login forms via injected scripts (XSS = game over) and modify page's content via unprotected CSS and images (which aids phishing, clickjacking).
