I only have an iPhone to test with (which is known not to work with libgpod), but it looks like you'd need to load libgpod, libusb, gst-plugins-{bad, ugly} and (maybe) libmtp to use an iPod with rhythmbox.
..this gets me a bunch of rhythmbox error messages about not being able to communicate with a usb device at least...
Note that there's an "iTunes-like" browser plugin included with rhythmbox-2.7, but I didn't try this.