Although black is the most commonly used eyeliner shade, there are 2 great alternatives that provide a dark line, but aren't as dramatic as black.
Clockwise from top: Smashbox Jet Set Eyeliner in Intrigue*, MAC Eye Kohl in Teddy, MAC Technakohl Eyeliner in Steelpoint (LE), Bobbi Brown Gel Eyeliner in Chocolate Shimmer Ink
Brown Eyeliner: Brown eyeliner is great for fair to medium skined beauties because it is more natural looking than black. However, that doesn't mean dark skin tones can't rock brown. I like medium to dark shades of brown because it provides the intensity of dark eyeliner, without looking black. Personally, I wear a lot of brown eyeliner, both during the day and at night, most frequently when doing a brown smokey eye or when wearing natural or no shadow. My two favorites are Bobbi Brown Gel Eyeliner in Chocolate Shimmer Ink and MAC Eye Kohl in Teddy (both are permanent products)
Grey Eyeliner: In the same vein, I LOVE grey eyeliner because it is much softer than black, and really complements brown and green eyes. Again, I like using grey eyeliner with little to no shadow on the eyes. I love using colored eyeliner and grey gives me the feel of using a colored liner, but is still very natural looking. The trick here is to use a grey that is dark, not silvery, like most grey liners are. My two favorites are Smashbox Jet Set Eyeliner in Intrigue (currently part of Smashbox's spring 2012 release and it comes with a mini liner brush) and MAC Technakohl Eyeliner in Steelpoint (a limited edition liner that came out a couple summers ago and I wish they would re-promote).
L-R in Natural Light: Smashbox Intrigue, MAC Steelpoint, BB Chocolate Shimmer Ink, MAC Teddy
L-R w/ Flash: Smashbox Intrigue, MAC Steelpoint, BB Chocolate Shimmer Ink, MAC Teddy
Other colors like dark navy and aubergine are also great alternatives to black, but are also a bit more adventurous than brown and grey.
*Disclaimer: This product was provided by PR for consideration. As always, my thoughts and review reflect my honest opinions.