Corsair

Corsair doesn't make anything that truly matters performance wise, like a CPU or GPU. However, you can furnish the rest of your system with corsair components, and honestly I got something to say about the quality of them all.

RAM
RAM is RAM, honestly. RAM shouldn't differ as long as it's the same frequency / DDR type. The thing I love about corsair is, past G.Skill, it is one of the cheapest RAM manufacturers while still providing quality RAM.

Cooling

I wasn't expecting much of my stock case fans from Corsair, but truth is, they work great (Corsair AF series) They're very quiet at max speed, and I have yet to own a fan cooled system as quiet as the one with these fans. I'll probably reuse these often. Also they cater to those with a taste for glowey-LED fans.

I also have great things to say about my Corsair H60 closed loop water cooler. On my AMD FX-6300 overclocked to 4.6 GHz, the idle temperature was 20 degrees C ; close to room temperature. Under load it still has not eclipsed 60 C, for a 50 dollar CPU cooler. Installation was easy in my case (coming up) and the noise level is next to none.

Also, corsair's water clocks for GTX 1080s are out and quite nice, I hear.

Cases

My machine features the Corsair CARBIDE Air 240 case, and I love this thing, okay. It came stock with dust filters for all main vents and three case fans ready for use, plus three hard drive slots AND three SSD slots. And it can still fit all full size components (save for the mobo) Even if that doesn't fulfill your needs, the Corsair CARBIDE Air 540 is the same thing but it comfortably supports all sorts of motherboards (up to E-ATX I believe) 

These cases are both great cases, I love the thought of design in them but it doesn't stop here ; 

Corsair SPEC-01

Corsair 200R

This is one of few good cases I have found that can actually fit high profile CPU fans, such as a Cooler Master Hyper 212 EVO.

Power Supply

I appreciate the quality of Corsair power supplies. They're all nice, and the power draw ranges from basic to titanium, and wattage over 1500 to suit all of your needs. I consider them up there with Seasonic and EVGA.

Peripherals

Corsair also makes nice keyboards, headphones, and all that jazz. I 1-up their VOID Stereo headsets, very great (especially for 50 dollars price) but I give the keyboard credit to my CM Storm Devastator. Still the cheapest, simple, but functional and good for the 20 dollars with the mouse included.

Their mice are all very great, and their Strafe RGB keyboards are certainly great to look at, thought quite pricey, they might be worth it. All of them have nice build quality (as corsair has always delivered) and overall their peripherals are some of the best for the price point.

Overall ; Corsair is a company that makes high quality gear at a very affordable price point. The quality of their products exceeds my expectations for price points ; my $50 corsair VOID stereo? Rivals my old $200 Turtle Beach PX headset that I had. Air 240? The best case I have owned, period. CX550M? Great quality power supply, and it's lil' bro, the CX450M, is the one of the best at it's price point. I'll trust Corsair for a long time.