I agree that you’d need to make sure you have an edition with a set of good maps unless you find something online to consult regularly. As far as translations go, I’ve used Crawley the most, but don’t have a strong opinion. In my opinion, the choice of translation is much more critical for works of poetry.
Thank you for the suggestions. I went with the Landmark editions of Herodotus and Thucydides. I thought it’d be fruitful to read both. Reading either one without the footnotes and detailed maps would have been pointless, I now realize.
Be sure you start with Herodotus, because Thucydides distinguishes his approach from that of Herodotus. It will be good to know what he means, and to be able to read his book with what he says about that in mind.
Actually, there aren’t dozens of translations, only about six. Many of these are reprints; for instance, 978-0226801063 is a reprint of Thomas Hobbes’s translation from 1629. Hobbes was a great writer, but his English is of course a bit archaic, so many people find it hard to follow. More recent translations are Crawley (1903), Rex Warner (Penguin, 1972?), Lattimore (Hackett, 1998), and Martin Hammond (Oxford, 2009). I haven’t seen all of these, but I’ve always liked Warner, FWIW.