In anticipation of the X1, I am setting up a computer to use with it and also use on my workbench.
I scored a Dell 790 with a Core I3 and 16 GB of ram for $5.00. I upgraded the CPU to an I7 and installed an older NVidia video card. The computer is a slim chassis so the cards needed to be half height. I actually found the half height slot covers for the video card and vga connector on Thingiverse. Add a $11.00 SSD and USB 3.0 card and Voilà, a cheap computer that is actually usable.