One more comment on coping - the document I linked to shows two different approaches to transferring the profile of the moulding to the piece you're coping. I personally use the mitre-then-cope approach rather than the trace-then-cope approach. It's faster and more accurate.
Also, the article doesn't mention it, but I find that rat-tail and half-moon files are very useful for fine-tuning the fit of your coped piece.