This is something ive been thinkin about for a bit and wanted to suggest (not sure if it has been already).
It would be an informal effort listing all the harp keys and a description of each one.
for example which are the best for the blues (with a few examples of famous blues songs in that key (when i say 'that key' i am of course referring to the key being played in 2nd position)), which keys are good for straight harp (again with examples of some songs).
of course i guess it comes down purely to preference as the relative notes are the same for every key, but some keys seemto be easier to bend and some sound mellower. also it could be a place to discuss special tunings.