where to put temp gauge?

[Worminater]

I have a front temp display on my case, and am debating where to put it the senser... I currenty have it sititng directly under my 6800gt, but probably not in the best spot. Where would you guy suggest? the 6800 is a 2 blue fan bfg btw, and I would like it to give core temps on that but Im not sure where I can safely stick it under the heatsink...