How do you mount temp sensors?
 

Title expalins it all -

How to attach to w/cooled CPU & GPU plus HD?

Please help as I want to close this bloody computer case forever!

I suppose you ask about flat tipe temp sensors. If so, the easy way is to stick it with a tape (I dont know the english word) to the side of the CPU with a tip of a sensor touching the side(not the top) of a CPU. You can also put some thermal paste on the tip of the sensor if you want. There is option to put the sensor from the back of the CPU but I think it will be too complicated and you have to modify the sensor wires.

For the GPU stick the sensor from the back of the video card behind the GPU.

On the hard drive you can measure from the side or from the top. Sides should be a little bit hotter than a top. I dont know can you stick the sensor from the bottom.

Hope this helps.

Tape is correct. Couldn't you put it next the GPU too?

Maybe you can but I would personally stick it from the back of a GPU. Back of the CPU should heat more than a side so I think its the same case with a GPU.