I'll add a bit of a legal perspective into the game. Disclaimer: I hold a Dr. rer. nat. from Germany, though lived and worked in several other countries in the EU.
Firstly, personally I think, that "choosing a title" and seeing it as an important issue, is largely a German/Austrian/(Central European?) specialty. After all, why should your title matter outside academia, where the difference is anyway largely understood around the world?
Secondly, even when you hold some title from country X, you are not automatically eligible to use it across the border, even given there exists an equivalent one in the other country. Rather, there are legal procedures which lead to a formal recognition and proper translation of your title. So for me, being a "Dr." with a title from Germany, to be able to use either "Dr.", or "PhD" in other EU countries, especially those east of Germany, I would have to either undergo a formal procedure called nostrification, or, in selected cases, if the university is granting an equivalent degree in my specialization, they could forgo the nostrification hassle and they could recognize it right away (rather and exception to the rule). Either way, you need to obtain a formal certificate from the state, or at least the university, stating exactly how your title translates to an equivalent title in the other country. Only then you can use the title freely. To top it up, the whole matter is regulated by bi-lateral international treaties between countries exactly stating which title holders are eligible to use which titles in the other country and how. See for example the treaty on grades recognition between Czech Republic and Germany. There even is a full website in Germany on all this (mostly for foreign title holders wanting to use them in Germany).
To sum it up, there is a whole lot to simply using an academic title in a country different from the one you obtained it in. This can be straightforward in countries where the culture doesn't care too much (in my experience e.g., Netherlands), but in countries where the title can be legally a part of your name (not sure whether it still is the case), such as almost whole Austrian-Hungarian empire heritage countries, this can be a big deal.
My point is the following: It's probably irrelevant which title you choose. If you want to be precise, legally speaking, somebody probably already translated your title to another one (which you can't choose) which you should adopt in other countries.
Apart from all that above, I regularly see people approaching me in e-mails, or letters by both "Dr. XYZ", as well, as "XYZ, PhD" - not speaking of those not checking the background and virtually promoting me to levels I do not belong to (yet). Again, the precise title doesn't matter that much after all.
Later edit, on a more anecdotal note:
the precise title doesn't matter that much after all
Well, except when you want to use the title for things like skipping a queue when visiting a doctor and being treated very respectfully by all the nurses (Germany), or when encountering police, getting away with only with a warning and avoiding a fine for speeding, or other minor trespassing (countries eastwards of Germany). I have first-hand knowledge of such incidents, so my advice here would be to 1) go for the fanciest possible title, yet it should be widely recognized by general public, and 2) if your country of residence allows it, include the title on your ID card, passport, social security ID, whatever else, so that you can wave it when necessary :-D.
