Sorry to bust the bubble. There are real differences between the white silicone compound and the compounds containing microcsopic size metal particles. I work with electronics and can confirm it is so.
Here is and interesting review for you to read.
http://www.techwarelabs.com/reviews/cooling/thermal_paste/index_3.shtml Reviewed by Jason Jacobs on 08.13.2003
It does not stop there. Polishing the CPU and Heatsink contact surfaces (the shinier the better) with waterpaper also makes a huge difference. Remember a huge differenc in electronic's may be less than a degree celcius.
Yeah sure the point of the compound is to remove any air pockets that's why polishing improves the performance. However my point is colouring it with blue or silver is all hype and people are paying a premium for that believing it works any better than the stuff that's been around for ages.
http://www.fongyong.com.tw/en_product-silicone-thermal-compound.htm
Heat sinks compound / thermal compound is a white paste silicone product heavily filled with heat-conductive metal oxides. The incorporation of high efficient heat-conductive metal oxides promotes high thermal conductivity, low bleeding, and high-temperature stability. Up to approximately 300oC, the product is very stable to changes of temperature. It helps to maintain a positive heat sink seal that improves heat transfer from the electrical / electronic devices to the heat sink or chassis, thereby increasing overall efficiency of the devices.