Spray Equipment / House painting??

Any recommendations on a spray rig for use around the house? I have some pretty big projects that will require spraying and I don't want to be filling up or lagging around some little pos with two quarts of paint in it. On the other hand, I don't want to spend $800.00 on something that will see limited use. Rentals are looking like $75.00 a day or $250.00 a week, not real feasible to rent four or five times in the next year. So, middle of the road at about $400.00, what should I look for? Want to make sure it is something that can be maintained with replacement parts available in the future if necessary.