I've tried to get my Nginx proxy to serve files instead of Rails (via x_send_file) which according to what I've read should fix/slow down some of the memory leaks I've been struggling with lately. Please let me know if you experience any problems with downloading files or seeing your logos or avatars.
That didn't seem to have much effect, so I've tried upgrading to Rails HEAD as they have done lots of memory fixes lately. Please let me know if something has broken for you.