As far as major components go - a PSU bought in December '09, 600W Coolermaster. It's now powering the third build since I bought it.
As far as peripherals....my wheel and pedals. An ancient MS Sidewinder set that I bought in 1999 for Grand Prix Legends (I'd been using the keyboard up until then, not exactly the easiest of racing sims to control that way!). Only had minor repairs over the years (wiring, a switch or two) in spite of all the hammer that it's had.