Why not just get one of everything over time? you can always move to a bigger house when the time comes
For the record chez fluffy has 3 xboxes, a megadrive, a master system, a gba colour, psp, ps1, ps2, atari 2600, wii, and I plan to add to these when the new house games room is finished. Its even marked on the plans we submitted for planning as "projector room"
I think the wii on a barco projector takes some beating if you have friends round and beer is involved. Although watching drunken relatives making a fool of themselves on xbox dance dance revolution on the mat controller is also quite fun. I wont buy a 360 until its hacked properly. Havent looked in a while.