What value for a Rfc2898 (PKBDF2) is overkill? I am working on a project which needs to share messages, and part of that project is deriving a password, I am currently using a value of 65537, totally arbitrary (it is $2^{16} + 1$, so not TOTALLY) and that takes about 1-second to compute. but, I just wondered what value or iteration count is enough? 

Note its just a hobby project, not a federal info. transfer thing.
what value or iteration count is enough?


So in NIST SP 800-63B a baseline of 10,000 iterations is recommended. Going below that is a really bad idea.

Now of course the actual guidance is "do as many iterations as you can afford", which usually amounts to "do as many as your users are willing to wait for". If 65,000 already take 1 second and your users will complain enough about that to go for a different application lower the value. If they're patiently waiting 5 seconds, go for the iteration count that takes 5 seconds.