I'm still working through a bit of a hiccup with using my Amahi calendar with Evolution, so I thought I'd install Thunderbird and Lightning to see if they worked. The problem with Evolution and my Amahi calendar is that no matter what I try, the calendars on Amahi are flagged as read only. I understand that it will be read only (at least potentially) with a pre-existing calendar, but even when I create a new one I can't add new appointments to it. Not good. ;-)
Thunderbird is easy enough to install with apt-get install, and Lightning is just an add-on to Thunderbird, but on both my 32-bit and 64-bit machines when I launched Lightning the "new calendar" option was grayed out. A bit of scroogling showed that Lightning has a dependency on libstdc++5. The issue is that beginning with Ubuntu 9.10 libstdc++5 is no longer in the standard repositories, so sudo apt-get install libstdc++5 no longer does the trick.
Now it's time to ping the Amahi folks about the read-only issue with Evolution--I was liking Evolution until I ran into that.