Do not worry, Regullus, Corvis is always mad.
"What to do?" = translated into english as "What is to be done?". a classic text, i've still got it on my bookshelf.
while you are right - the "what's to be done" is obviously a proper English, I think it has a bit of more "practical"/"sure" sound to it, while in the Russian title the helplessness of the phrase always bought me (I can be wrong of course). Other than that the book left mixed impressions on me (mainly because of Vera Pavlovna's dreams... gods give her insomnia), but the title was great.