Here's my system, in all its glory.
Just a quick explanation. I live in a very small house, and the space you see in this picture is the "laundry room", which is part of the larger "back room". The kegs are sitting on an old B&D workmate. The pump sits on an inverted pot. I pull the dryer out to plug the system into the dryer outlet, and rest the HLT and control box on the dryer. I use the laundry sink for water and as a drain. To the left is a doorway into a bathroom - I turn on the bathroom fan to vent moisure during the brewing process, and this does a reasonable job of keeping condensation down in the house.
The second photo shows the space sans brew system.
Here's a shot of the wiring. The control box is a "boat box" - a rugged water-resistant tackle box from Canadian Tire. I got a friend who knows a lot more about this stuff than I do to help me out. Basically, there's a 110V feed (orange wire) which powers the PID and the outlets. There's a 220V feed (white) which connects to the SSR and element power (red). The white and black wire connects the RTD (temperature probe) to the PID.
Since this photo was taken, I've replaced the red and white wires with flexible wire, which is much, much easier to work with, and probably safer.
Here's the controller close-up. I have another digital thermometer I use for calibrating and getting a "second opinion" on the RTD and keg-mounted thermometers. The outlets on the front of the control box are used to power a fan and pump.
These next few photos show the couplings and elements. I'm using two 3kW hot water heater elements. There's nothing special about them - they cost $15 from Home Despot. The couplings are 1" NPT couplings. Yes, the elements are straight thread, which theoretically are not compatible with NTP threads. In practice, they fit fine, and the rubber gasket around the element gives it a water/wort-proof seal.
Here you see the PVC plastic "shroud" I made for the elements to cover up the electric connections. I first sealed both ends with regular 2 part epoxy, but it softened at the element end, and eventually broke. So I used a super tough epoxy called JB weld, which has worked a lot better.