Got 5 mil, how do i get rich?

Scrounged together 5 mil in gold by unid item gambling, now looking for a more stable and profitable source of income. I currently have a barb that is geared for a1/a2ish, and a dh on the way to inferno. How do I make my money breed and multiply? Gear up one of the characters and farm? What kind of gear am I going to need in either case?