I am going to go liquid cooling soon and i was looking at radiators from danger den and was wondering if i should go with a black ice or a thermochill. and also whats different about each of the black ice types, like the gtx , extreme and so on

Don't know much about liquid cooling but my guess on your question would be that different radiators vary in efficiency, power consumption, noise, coolant volume etc... There are also radiators that feature dual cooling fans for added heat dispersal. Just choose the one that best fits your setup (and case). If you only have a few water blocks in your system, I would just match the size of the radiator with a single exhaust fan slot.

I have found that 120 radiators are pretty pointless, so start with a 240 or up.
I am now using a 360 PA.3 Thermochill and a 360 Black ice pro 3. There is a difference in performance with the Thermochill being slightly better.

The differences in Black ice rads is about their performance with different fan configurations. Some work better with lower (therefore quieter) airflow. Others perform better with high speed air, which of course has a noise penalty.

The best performance I have is by using fans in a push/pull configuration, so although that means running 6 fans on a 360 radiator, the cooling is excellent. I can run both my QX9650's at 4.2gHz without exceeding 55c at full load.

As my computers run at 100% load at least 20 hours a day, this type of cooling is the only practical way to do it.

6 fans might give the best performance, but unless they're very low cfm fans, you'll have to deal with a tornado-sounding cooling system. Some people don't mind, so...

But I agree that a 120 radiator on its own will be pretty crap.

Also, as previously mentioned, there are radiators designed for high cfm fans, and other radiators designed for low cfm.

Whats not been mentioned yet is single, and double pass radiators, or the cross section of those radiator tubes. Can't remember much about these already, but a short google will guide you more about your choices than a "I think this radiator is good" reply.

You didn't say what you're going to water cool but with many processors producing fewer watts of heat these days a single thermochill pa 120.1 will be more than enough cooling power for the average dual core Intel processor or any processor producing less than one-hundred watts. Push pull fan setups don't usually outperform single pull setups by a wide enough margin to justify the extra expense and noise. Thermochill radiators usually produce far less back pressure than their close competition, meaning that your water pump will have an easier time of circulating coolant through the loop keeping your processor cooler. A radiator designed for a slow fan will work even better with a high speed fan. Didn't you post this about a year ago?

so what is a push pull configuration, and i thought the black ice 360 can only have 3 x120 fans?

A push pull fan setup is a set of fans on each side of the radiator. One fan pushing air into the radiator while the other fan pulls air away from the radiator, so if you bought the Black-Ice 360 and set it up in a push pull configuration you'd have a total of six fans attached to the radiator. Radiators usually have fan mounts on both sides of its' frame.

I doubt anyone would now run a relatively expensive water cooling set up in order to cool a dual core CPU. With Q6600's now being very good value and an excellent overclocker, it seems like the obvious choice for even a fairly budget system. Dual core CPU's can usually be very effectively cooled with high end air coolers.

At 3.6gHz this will produce around 160 watts of heat, so a 360 would be the sensible choice.

Another advantage in buying a 360 is that what ever system you build, or any other cooling requirement you add, the 360 should be able to cope. A lesson I learnt myself when I found that the 240 which cooled my E6600 perfectly well, struggled to keep the temperatures of a Q6600 under control.