Irregularpulse is right, there's all sorts of configurations. The only thing that is a must is a boil pot. If your not directly heating your mash tun you don't need a pot there. Mashing can be done in coolers. Sparge water can be heated in your boil pot and stored in a cooler as well. I use two 10 gallon kettles, one for boil and one for HLT and a round 10 gallon cooler for mashing. That's a pretty typical setup around here. You can make great beer with a minimum of equipment.
Beer, if drank with moderation, softens the temper, cheers the spirit, and promotes health.
"Give me a woman who truly loves beer and I will conquer the world." - Kaiser Wilhelm
"I would kill everyone in this room for a drop of sweet beer."- Homer Simpson