This is another old post, but I've added a bit more for my long-time readers...
Germane v. Relevant (DD definition links)
What is germane to this exercise is that we enjoy using the words, and find interesting ways to integrate them into our normal conversation. That was just too easy, and unfortunately, since I went to law school, my word has always, ever, only, been "relevant". Sorta becomes the red flag that I'm a lawyer (as if practically everyone didn't already know that) and raises the evidentiary issue, just for fun. Plus, the way I say it, it sounds like an objection already. There is no obvious noun form for germane (germanance???), which makes it impossible to use in the same way as just saying "relevance", with that indicting tone. So, although I like germane, its relevance for me is fleeting.
I suppose the real issue for me should be that germane derives from Latin for "of or relating to the same parentage" and relevant comes from Latin for "to relieve, raise up"! Neither of these etymologies have any obvious bearing on the connection of two items or subjects. So how did this words come to have this meaning? Does relevance "raise" a related issue somewhere of some type? While germane quite literally has the germ of the idea which grows directly into something else? Germane also has a latent meaning of being "closely" related to the issue and not any type of relation. Therefore, it appears that germane is more closely connected than mere relevance, which may be only tangential. But in law, relevant is relevant, regardless of the attenuation. It's still "relevant" for me, and possibly germane for anyone else.