i would prefer a good air system over a closed loop. but a decent real water cooling system is worth the effort if you get the biggest reservoir you can to go with it. in order of importance for me in a water cooling system is. water block needs to be good and substantial.. i prefer a thick copper base not crazy thick though. but not one of those blocks thats basically a copper shim screwed on to some acrylic.
reservoir needs to be separate to the radiator, separate to the pump and hold a lot of water,
Pump has to connect to molex/sata connector for power from the psu not from a fan header the pump can be a reservoir+pump type but does not mean you wouldn't want the a fore mentioned reservoir. and needs to move as much water as the pipes can handle.
radiator needs to be able to have 2x 120mm fans mounted to one side of it.
The only problem with that is even with a decent sized full atx case you can end up with needing to keep the reservoir outside the case. (unless you get a 2/3 bay 5.2" reservoir
And i also recommend putting a flow indicator on one of the pipes some where that you can see (need a clear side panel for that)
the only way you can really get the perfect water cooling system is to buy all the components separately.
the water block and the pump would be my main concern, followed by the radiator. those 3 items are what will cost the most.
The reservoir can be bought for less. if you have enough bays you can even buy 2. and hook them together.
you need to make sure that they will all work together with the same fittings.
and i do recommend having little stop taps that you can close off for when you want to drain the system.
not sure about what the prices are where you are, but over here in the uk a decent custom loop you built your self from parts would probably cost quite a bit more than $200
-=edit=-
went off to a water cooling sales people and the parts to make a reasonable custom loop without postage came out to about £180 which is a lot cheaper than it used to be.
thats pump reservoir rad fittings tubes but no fans 2x high pressure 120mm fans shouldn't take the overall figure above £210 though even if you wanted decent fans rather than some generic ones..
looking at it like that i cant see why any one would buy a closed loop..
Ah man it all sounds abit too complicated, like I said I would really much prefer something easy to install like the h75, but thanks for your suggestion. Maybe one day I may consider it, now that I have this very good gaming case.
EDIT: I previously had the coolermaster hyper 212 evo, even though it was doing a pretty good job at cooling my cpu, every single time I had to take it off and put it back on, I found it to be a real big big serious pain in the ass to install back in. The h75 on the other hand was a lot easier than I expected, and atm loving it so far, besides the fact that its not performing well enough for me to overclock my cpu further. So I'm planning on getting a new cooler to overclock further, or maybe buy a new cpu like the 8350 and keep my h75, but I won't really be able to overclock it much I'm guessing. I'm also thinking about the fx9370, and believe that it requires liquid cooling, and as I said I'm still looking at the corsair h100 series. So far I'm quite interested in the H105.