Compose key is a great way way to write all these ©–®—… stuff. It's really MUCH more handy than the windows "alt+0169" method.
Is there a way to define additional sequences? E.g. I'd like to have "Compose+-->" result in "→"
The Ubuntu documentation has some info about this. It looks like their instructions are fairly distribution-agnostic; however, I haven't tested them.