If you're in an early stage and seeking seed funding, then you should have everything thought out before talking to investors. Don't ask investors to help you decide which of the founders should be CEO because they'll take it as a sign that your partners and you can't work things out on your own. Investors want confident people who know what they're doing and go for it; they can smell fear and they'll disappear before you finish asking the question. Remember, it's YOUR company and it's YOUR responsibility. Investors help you with funding, introductions, and, maybe, some advice; but don't let them run your company for you. On the other hand, if you're in a later stage and seeking big VC funding then it's a whole different story. Talk to experienced entrepreneurs or close investors about the specific details of your situation; theyll give you great insight. Although the key princeples are the same: it's your responsibility and you're expected to have strong leadership.