Thanks to everyone for the help so far. It turns out that I really 
did poison my system by using the precompiled binaries for some 
things, so I have to trash the system and start over. This time, I'm 
not going to set LOCALBASE, and will use /usr/local for really local 
things.

I still would like the package gods to consider my suggestion from last night:

>Another thought: can pkg_add be changed to not allow a user who has 
>a different LOCALBASE to add by URI, or at least force them to do so 
>with an additional command line option like "-d" for danger?

I don't think that documentation changes telling about the possible 
problems with resetting LOCALBASE is enough. Given that pkg_add can 
help prevent the problem, it would be nice if it contained the 
warning.