BTW lapping aint for l33t PC geeks, I did it for 15years as a engineer, we had to mate surfaces gas tight like Valves in Cylinder Heads etc.
We used Grinding Paste, rough then smooth, you can then test with a stuff called Engineers Blue, it marks the surface you put on and when you mate it to other surface and then remove you can see any high spots.
I use Wet/Dry paper same as all others but its not as easy at home and holding tall heatsinks is hard not to coggle, its also damn hard to get the diff sizes of grit paper, nobody seems to do own car body repairs these days.
All the photos in this thread look good to me, flat and shiny too, and even though they are shiny its impossbile they are too smooth and wont grip the TIM/paste, you would still see grooves through a mircoscope, you should Google for that view on a new Razor blades edge, it looks like a mountain range.