PC Water Cooling - Computer Water Cooling, Liquid Cooling Products
Computer Water Cooling -
Computer Water Cooling - FrozenCPU.com ?
Computer Water Cooling at Xoxide.com - PC Water Cooling
... and where I actually bought most of my stuff from, looks broken nowadays maybe it went out of business :-( :
Petra's Tech Shop
This should get you started. The products they sell are largely the same, so I'd just buy from the cheapest place as usual, depending on promos and what you're getting. Maybe buy from several different places if you like some barbs that another store doesn't have for example...
I recommend that you don't go cheap on the pump if you're going to go 2 video cards and a CPU. A MCP-655 used to be the "best" single pump, but that was like 4 years ago. It's probably still an excellent pump (I have one, and it's still going fine after 2+ years of 24/7).
Also, I'd recommend 1/2 tubing for your entire system. Cheap pressure clamps and simple barbs are fine IMO, unless your name is Sixer and/or you shit money.
Simple distilled water (from your nearest grocery store) is the best fluid that won't shit up anything. Just get a silver coil to put in your reservoir and a few drops of biocide (I have a couple of these, but like I said above I'm not sure if this shop is operational anymore):
Petra's Tech Shop
I recommend that you do NOT dye your water, and imo do not buy precolored water or "water cooling fluid." The benefits over distilled water are non-existent.
Also, go copper/acetal or copper/acrylic or something on the waterblocks IMO. Nickel might cause corrosion in combination with copper, which is what radiators are made of (inside).
Uhmmm that's about it. As with any PC components, there are many detailed benchmarks out there, I remember one site which I was reading when I was about to buy my components which was dedicated to water cooling and their thermal testing is pretty insane. Can't remember the name, but you should be able to find it.
P.S. Also, I'm not sure if it's worth the money to spend on laboratory grade tubing. I got primochill blue color tubes and they've aged well so far and were fairly flexible to work with. Of course, I guess if you want extreme flexibility maybe lab tubing would be worth it to you.
P.P.S I reread your post after I already posted. You might be able to find a CPU "ready to go" kit that you basically buy and just screw in and it runs, but if you want to cool more than a CPU, you pretty much need to do it yourself AFAIK. You might be able to find "kit deals" but I prefer picking my own parts over some lame small discount that you might get for purchasing a bunch together...