This calligraphy pen-inspired tip is perfect for creating a cool, graphic look. The slant allows you to easily draw squared-off, straight edges and shapes. (Note: While the pen simplifies things, these techniques are not for the makeup novice. You'll need a steady hand and an eye for symmetry to get a look like this right.)
If liquid eyeliner is generally too severe for you, choose one with a tapered, cone-like point -- you'll get a diffused line. This marker is also blendable while it's still wet, so it's the ideal base for a smoky eye -- you can layer powdered shadows right on top.
If you want to draw a line that's thick on your lid but tapers off to a thin line by your temples, this marker will do the trick. Hold it at an angle to draw a wide line, or apply it at a 90-degree angle to your face to create a thin mark using just the point of the pen.
If I know I'm going to have an 18-hour day, I opt for this eyeliner. It won't smudge, and it never creases -- you could sleep with it on (not that I recommend it), and it will look perfect the next morning. Of course, that means it's also extremely challenging to remove. (Try using Kiehl's Supremely Gentle Eye Makeup Remover, $16.50.) The color is extra black, so be prepared for a less-than-subtle look, and the point is medium thickness. And because it will never transfer, it's ideal for experimenting with lines under or over the lid.