I’m currently debating which language to study next. I’m currently focusing on Greek, and I’ve studied French for years. Both will be necessary before I (God willing) do doctoral work, but I’m currently leaning toward Latin.
The crux is this: I’m on a waiting list at school for a free Rosetta Stone license. I get to pick any one I want to use for 2 months, and they have both Latin and German options. I’m leaning toward Latin for several reasons. First, I think I want to do research on the early Church, and not just the New Testament. Thus, Latin is obviously important when dealing with the Western Church. Second, I don’t think Latin will be too terribly difficult. Vocabulary-wise, I expect to know quite a bit from French. Grammar wise, I expect a lot of similarities with Greek (though I could be totally off base here…). Third, Latin just seems more interesting ;-).
Of course, German has its plus. You open yourself up to a load of secondary literature, but I’m wanting to read the primary literature first!