Very simple mani made with HK water decals on a base of Diamond Cosmetics Starry Night, a black with subtle silver glass flecks. I wasn't quite sure at first what base color would be appropriate, but with the punk theme, black seems like the obvious choice. I thought it would look too cheesy, but I actually really like it! The decals were too big for my nails, so I carefully cut them up. I accidentally put the HK head upside-down, though, D'oh!
Now that I've tried them, I prefer water decals to stickers because they are thinner. It makes it easier to mold them to the nail and cover them with top coat. Stickers sometimes stick out at the edges because they don't bend as easily, but they can be more 3D than decals. Water decals are also easier to cut into pieces if they are too big (or you just prefer them that way).
You can buy the decals from this ebay seller: hello2happiness