Originally posted by Rory 2 is my fav as well. 3 would be great if it weren't for a few distractions (mainly the lightpole). Impressive high ISO. I always feel grainy at 1600 with my Kx. What do you do NR on? I guess I should try some different techniques.
#2 was at ISO6400 I believe, with NR in Lightroom of ~50% strength. IMO anything under 3200 looks fine with just some colour noise reduction, I love the grain it tends to give. As far as "techniques" for avoiding high-ISO's/grain, there aren't really any. Given that I have to shoot at 1/300 minimum to avoid serious motion blur, and my kit lens is only F/3.5 (and I prefer to keep it to F/4+ if i can help it) there isn't much I can do about it. Worst thing you can do in post is try to raise the exposure, I like to add to the darks (especially with a lot of "almost black" like in #2) to darken the shadows and remove a lot of noise.
If you looked at the results straight out of the camera, they would still be QUITE grainy. LR3 has an amazing, amazing, amazing noise reduction system that has saved my life quite a few times. I actually find 12,800 usable for night shots!