Painting whole house w/ spray gun -- ceilings, wall or trim first?

[Zoran M.]

I recently signed a contract to purchase 3,200 sq. ft. duplex. In order to stay within budget I intend to paint the property myself. Given the size, I will be using a Milwaukee Airless Paint Sprayer ($249 at Home Depot!) rather than rolling it all by hand.

The ceilings, walls and trim all need to be painted. I've read a lot of various opinions on which needs to be done first and wanted to get the BP community's take on the matter. I currently plan on doing it as follows: 1) Ceiling, 2) Trim, 3) Walls.

Is this the best course?