H320 X2 Prestige CPU Liquid Cooling System
One of the most noteworthy aspects of this kit, is that it's available in a few different models. This one, the H320 X2, has three 120mm fans which means it functions as well as any other 360mm radiator out there. The other models have a pair of fans, one with two 120mm fans and the other with two 140mm fans which gives you great options if you don't want the 360mm model. This kit comes with everything you need for set up including a radiator, multiple fittings, and pre-filled tubing. LEDs are included to make the cooling system stand out visually and three different dye colors are also provided so the liquid in the tubes can appear red, blue, or green. This kit works with both Intel and AMD CPUs which makes it a great option for a wide range of computer builds.
XSPC RayStorm Pro Twin D5 RX360 V3 WaterCooling Kit
If you have an Intel CPU, then this is a great option, but that limitation keeps it from being the absolute best choice on the market. The reservoir is easy to use and watertight, the pump works effectively, and it all connects to the waterblock that you can easily install onto your CPU. There are three 120mm fans that come with this setup, which gives you great cooling and ventilation. It includes about six feet of hose for set-up, and even includes thermal paste for installing the CPU water block on your processor. XSPC provides white and blue LEDs on this kit for a clean, sleek look and it's designed to work with multi-core CPUs for optimal cooling performance.
EK Water Blocks EK-Kit L360 (R2.0) Water Cooling Kit
This kit has pretty much everything you need to get a computer set up with liquid cooling. All the hardware you need, including the pump and other attachments, are all included and set up is pretty straightforward and simple. It has 2 meters (around 6 feet) of tubing for you to use inside your computer, which should be more than enough for just about any system. There are three 120mm fans included with this kit, which is great, but you will need to choose a different model if you want fewer fans or ones of a different size. It lacks much of a "wow factor" from features like LEDs or colored coolant, but it works well. This kit supports a number of different AMD and Intel processors, so it is a great choice for a wide range of setups.
There's a lot to like about this water cooling kit and Cooler Master has it available at a number of different, standard retailers, which makes this a more accessible option than some other kits out there. This is a 240mm model that includes two 120mm fans. That means there are certainly larger and more efficient coolers out there, but you're not likely to need them unless you're really overclocking your system as much as possible. This is also an expandable kit so you can install this basic hardware and add more tubes to it for additional cooling later. That makes this ideal for people who are new to liquid cooling, though it's still a great option for use even by experienced computer enthusiasts. The support for both AMD and Intel CPUs is also excellent since you can use this kit with just about any modern computer on the market.
Alphacool NexXxos Cool Answer 360 LT/ST Set
There is a lot to like about this water cooling kit, but it is just a bit too hard to track down in the US to make it the best choice overall. It comes with a pump and reservoir, along with all the tubing and fittings you are likely to need. The tubes are nice and wide for easy liquid flow and it includes coolant that works much better than water. This is a 360mm model thanks to three 120mm fans that keep your system nice and cool, even during serious overclocking sessions. You can use this kit with all the current AMD and Intel sockets, so it's a great choice for a wide range of different systems. The real weakness of this one is there's a limited number of retailers that carry it in the US, so it can be a bit hard to track down. You can order directly from the manufacturer, but you will have to deal with European conversion rates.