read this regarding cpu idle temps and properly calibrating your software Real Temp - Documentation
dont worry at all about idle temps they will be wrong , most likely up to 10 degrees out either way , only worry about your full load temps and remember even water cooled systems with the cpu on idle can only manage a few degrees ubove ambient , if the rooms warm the water will be the same temp.
Core i7's have a much lower slope error than older cpus so the idle temps may well be a tad more accurate but as intel always states its temp hardware is there ONLY to throttle the cpu if it reaches its TJ max they were never meant to accurately monitor temps
One more thing after much research by Mr realtemp (uncleweb) it has been found that in a quad core two cores may have a higher TJ max then the others , to stop any system completely shutting down if it reaches its TJ max (max operating temp , which is differant of course to its safe operating temp) for example core 0 and 1 may have a tj max of 100 degrees and core 2 and 3's tj max may be 105 degrees , this will immediately put any two cores 5 degrees out of scew when monitoring , this is why you need to properly calibrate your software (in my opinion its not worth the hassle )
hope this helps , if you need any more info just ask
EDIT...............just seen your edit lol , theres is something wrong with his watercooling rig , he needs to sort that out
what is he using to monitor his temps?