Well if you're running this hardware you are going to need a good sized case. I'd go with a fulltower form factor. Personal preference will play a big part in selection. Do you like aggressive case styles? If yes consider the HAF X by CoolerMaster. If subtle is more your style I'd go with Corsair perhaps the 800D. That is what I am using for a custom open loop and it has been great.
After you've selected a case decide if you are willing to maintain and keep an open loop. Open loops have regular maintenance requirements which you'll want to keep.
Honestly the only component that should be watercooled at this point is your cpu. A pair of GTX660's do not need watercooling. I would suggest using a closed loop system to start.
The closed loops don't have any upkeep or maintenance requirements and for cooling purposes it will do worlds better than stock.
Open loops require several major components which each can cost what a closed loop system does.
1. Waterblock (cpu) - A starter block is $40-50.00 minimum. A full copper block will run $80-100.00+.
2. Radiator - Measure the fanspace you have available and TDP requirements for dissipation. When picking a radiator you have 3 different dimensions to consider. Length: fanspace is usually pretty accurate so 2x 120mm fans will make a 240mm radiator. Width: most of the time this isn't an issue but with unique cases and some radiators that stick out over the fan mounts. Height: NEVER underestimate how thick a radiator is. It can quickly add up and soon enough your radiator, fans, and rubber gaskets are just too thick for the space between your case and a motherboard, hard drive cages, etc.
3. Pumps: A pump needs to be able to circulate fast enough coolant. They are measured in LPH (litres per hour) or GPH (gallons per hour) and I'd suggest tracking how much fluid you use (also measured in litres or gallons for your convenience). But really this value is only important if you're cooling multiple cpus/gpus/etc. A couple of GPL or LPH is fine
4. Tubing: I can't explain all of the requirements here. Maybe another Tomshardware guru can expound on this? I chose mine for looks, size, and antikinking.
5. barbs or compressions? Barb fittings are cheaper. I can't say pros or cons as i've never used them. Compression fittings are downright awesome (in my opinion). I've used them several times and I like how secure they feel clamping down onto the hoses.
6. Reservoir (optional): for a single block basic loop you don't "need" a reservoir if you are using a good sized (240mm) or larger radiator. But if you do want one consider where it will mount. Some mount to the motherboard (by modding/drilling your own holes), some just fit in an "open space" in your case, and some fit into drive bays. I am using a 500mL XSPC reservoir that uses 5.25" drive bays for a mounting place.
most people do watercooling to set their rigs apart from the crowd so copying someone else's loop seems a bit impractical to me.
I am not a watercooling guru or even expert really. I've built half a dozen watercooled machines and each one has been a different experience with different parts and blocks. From what it sounds like I truly believe a Corsair H100i or H110i would fit your needs perfectly. Maybe another poster can offer a different opinion?