Let's not forget ear-scritches. Cockatiels like those, too.
(And cockatiels are also highly allergic to chocolate.)
Some specific badges might include:
Book Uploader - for first book uploaded
10 Books Uploaded
50 Books Uploaded
100...
500... (Yes, we need this!)
We might actually need one after that. How many has Patricia done again???
(I'm inclined against "most books uploaded," however, because I think that's against the spirit of MR.)
These could probably be generated automatically, since book uploads go in specific sections. Qualifying for multiple badges should result in displaying all of them, to my mind.
Then we might have "Software Contributed" -- I don't know as numbers are as important, there, but platform might be. E.g. "Sony Reader SW Contributed," "iLiad SW Contributed," etc. These would probably have to be by nomination to the editorial team, because software tends to be in attachments or even links to other sites, but it doesn't happen with the miraculous frequency of book uploads, so that should be ok.
It would be very nice if clicking on the badge would take the user to the relevant part of MR, though. E.g. clicking on a "books uploaded" badge could take one to a list of books uploaded by that person, the "iLiad SW" badge could take the user to the iLiad SW forum, etc. (No need to get obsessive about exactly where in the forum or which 500 books or whatever, just a general pointer.)
I'd also like to see, by nomination, "Thread Defuser". For people like Alex who try to keep things calm when the hot issues start to come to a boil.
This leaves the existing karma as a general "contribution to community" kind of feature.