Yeah, Mayhems is pretty much the best for fluids. I also agree with the primochill tubing, absolutely amazing. For blocks, you can´t go wrong with EKWB, but there are some other great brands, for example Watercool. Reservoirs are kind of the same at everyone, of course, some acrylic is bit better etc. etc. But mostly it does the job alright, again can´t go wrong with the popular brands. I personally don´t like Thermaltake, they´re bad. Mixed metals, their fluid just gunks up everything... Alphacool radiators are probably the best you can get. Fittings-Bitspower, EKWB,XSPC. Bykski is probably a good cheap alternative to those brands I mentioned. Haven´t used it but I´ve only heard good opinions. Also if you don´t mind cooling just the CPU, there are kits that offer (almost) everything you need. The only thing to buy is the ball valve, a splitter and an extender. I recommend guides from JayzTwoCents and Linus.