I rebuilt my machine almost completely last year. I do a considerable amount of gaming, so I felt obliged to sink a fair amount into this rig, replacing motherboard, CPU, and GPU, as well as replacing my two different monitors with two identical monitors.
I got the ASUS Sabertooth Z97 motherboard, paired with an Intel i5 4670k. To round that off, I got the ASUS DirectCU II GTX 780. I was tempted by the (at the time) upcoming 780 Ti, but my wallet started screaming "aw hell no" at me. I'm glad I didn't, as that would have been a stupid amount of money for a card that the Maxwell series is making obsolete.
To resolve my panel problem, I replaced two differently sized (but otherwise fine) Fujitsu-Siemens monitors with a couple of Dell Ultrasharps. They were particularly good purchases for their price, but still accounted for about a third of the cost of the upgrade.
I'm currently using a G19 keyboard and a G9x mouse. I quite like the GamePanel on the Logitech keyboards, so if they release a quiet-ish mechanical keyboard with the GamePanel, I might make a switch.
I'll also probably replace my case at some point, as it suffered an injury when I lifted it rather clumsily, pulling the top panel off and yanking out the LEDs and power switches in the process.
An SSD at some point would be nice too, but for the amount of storage I need, the current prices are far too steep for me.
EDIT: Almost forgot, I'm keenly eyeing up the Saitek X52 Pro to enhance my Elite experience. However, I recently bought the Moto 360, and I can't really justify spending money of more computer peripherals at the moment, especially when I already have a functioning joystick.