The standard answer you will get around here is to avoid the kits, as you will get better cooling at a lower price and more expandability if you choose your own equipment.
At the end of the day, it really isn't very hard to put together the parts yourself. Also, the guys in this forum and xtremesystems forums are really helpful and can sort you out if you ever get stuck. I did it about a month ago, and I had the same lack of experience/tools as you. Frankly it couldn't have been easier once I calmed my fears and decided to go the custom route. Now I am entirely addicted, and am going to spend this weekend adding more stuff to my loop and tweaking things.
FYI, I am also on a QX6700, and I am currently running stock and getting ~36C idle and ~45C full load. Here is my complete shopping list for my rig:
Waterblock: D-Tek Fuzion ~$65 (alternative Apogee GT ~$55)
Radiator: Thermochill PA120.2 ~$120 (alternative Swiftech MCR220 or Coolrad 22T, both ~$40. Even better, get triple versions of any of these for a little bit more)
Pump: Liang DDC+ (aka Swiftech MCP355) w/ Petra's modified top ~$100 (alternative Liang D5 (aka Swiftech MCP655) pump ~$80)
Reservoir: Swiftech Micro Res ~$20 (alternative, T-Line ~$2)
Tubing: 15ft Masterkleer 7/16 ID, 5/8 OD ~$0.49 per foot (alternative Tygon 1/2 ID, 3/4 OD ~$3.00 per foot)
Additive: 4oz Pentosin "red" G12 ~$5 (alternative 4oz Pentosin "blue" G11 ~$5). Mix with distilled water from the supermarket.
Clamps: 10 x worm drive clamps ~$0.90 each
Fans: 2 x Yate Loon D12SM-12 fans ~$6.00 each (alternative 2 x Yate Loon D12SL fans ~ $5.00 each)
Mounting: If necessary to mount externally, you can use a Swiftech Radbox ~$18.
Fittings: If you ever have a choice about what fitting size to go with, always go with 1/2". Also, a nice but not a need is to get 2 x Aquaextreme High Flow fittings for your radiator ~$5, 2 x EK High Flow fittings for your waterblock if Apogee GT ~$4
That should give you everything you need to get started. Assuming you are in the US, almost all this stuff can be found at one or more of the following shops:
http://www.petrastechshop.com/
http://www.performance-pcs.com/
http://www.jab-tech.com/
With regard to setting it up, there are a few great docs you should look at. I used
http://www.xtremesystems.org/forums/showthread.php?t=54331. Note that some of the info in there is a little out of date regarding specific components. Anyhow, a short short version of the basic idea goes:
1) clean the radiator and block
2) unplug EVERYTHING in your computer from the power supply
3) mount your parts in your case as best you can
4) run the tubing pretty much any way you like, except that the reservoir should come right before the pump
5) If necessary, put the ends of the tubing in hot water for a few seconds to make it fit over barbs. PUT CLAMPS ON THE TUBING!
6) mix your distilled water and additive (Pentosin)
7) fill up the loop from the reservoir using a funnel
8) make sure the pump has lots of water in it (DONT RUN IT DRY), then use your power supply to turn ONLY the pump on
9) run the pump for ~24 hours checking for leaks
10) assuming no leaks, plug in the rest of your computer parts, and you are good to go!
Please do read the full guide though for MUCH more detail, and in case I forgot anything.