Very good questions. I've always considered RMI more of a gimmick than anything else.. it seems way too inefficient and actually just plain silly to pretend to do normal method calls over a somewhat unreliable slow network connection. Yet it does certainly save you from coming up with something yourself.
Of course I think SOAP, CORBA, and DCOM are dumb too but apparently people really use that stuff.
I'm glad I can stick to 'fun' client side stuff. Hmm actually I did write a server for stuff at work.. I used a plain ASCII command interface, so without the client app you could still do everything with telnet. (Great for debugging too.)