I try to schedule thoughtful meetings and meetings with engineers for right after standup so people aren't yet starving for lunch and aren't breaking flow. Right after lunch is good for quick status updates or outgoing sales calls. Meetings with the sales team or CEO go wherever there's a free half hour slot on their calendars.
And my boss will talk your ear off on useless tangents, given the chance, so I try to schedule meetings with him for first thing in the morning if I need to make sure we don't run out of time; just before he has a meeting, if I'm having a busy day; or at the end of the day if I know he has to be somewhere and I don't.
External meetings: When it is convenient for the external party. Travel time is 3 hours? A meeting at 8 a.m. would suck because the party has to get ready at 4 a.m.
For east coat to west coast, 1pm est is 10am pst, and works pretty well