Macbook Pro 15" Late 2008 - 4GB
XCode 4.2 / Lion 10.7.2 / TexturePacker, PhysicsEditor, Zwoptex
Battery on Laptop even though it's within cycle limit is terrible, will sometimes just hard reset the machine after 5 mins off the AC. Have just bought 8GB RAM for it and a Crucial M4 SSD 128GB, tempted to go back to Snow Leopard.. Although Lion looks pretty the extra fluff is of no real benefit to me.
Virtual Machine
Snow Leopard / XCode 4.2
I use this when on my PC which is my primary machine.
@Birkemose you can have my 2x2GB (DDR3) sticks if you want, no use to me now.
I keep my main projects in github so it's easy to push/pull between machines.