The ultimate would be a lan with a $55 or more entry fee, but you get free food and drinks while you're inside, and you get to spend the whole day there. LCD screens have too much ghosting for my tastes, so unless you have the cash to shell out for big high quality LCD's, I'd suggest a nice big CRT. Each computer would be 2.5 ghz+, at least 512 mb of RAM, and at least a Geforce 6600GT-class video card. Sound card would be a standard Audigy2, and headphones would be Sennheiser HD555's. The mouse would be a nice CORDED logitech, since cordless causes too much interference with other mice and equipment. Mousepad would be a Fatal1ty pad or a Func1030 or something of equal quality. Mousepads and mice should be kept as clean as possible; this is important. Tables would be circular as to prevent screenpicking, but you can still give other players manacing looks if you wanted to. There would be security, because God knows teenagers think their gaming is the most special thing in the world and must be defended. The lighting would be adequate for you to see where you're going but not enough to distract you from your monitor's light. Every chair should be big and comfy and padded. Temperature should be kept at around 70 degrees.

That's all I can think of for now.