For my readers in Taiwan ...
Chic Choc's Waterproof Magical Liquid Eyeliner in black is my favorite liquid eyeliner, and I use it every day.
The brush tip elegantly tapers and never frays, allowing application of a very close, straight line against the edge of the eyelid.
The liquid inside also lasts forever. With daily application I'd say one pen can last me almost six months. I also like that when the ink begins to run out it simply starts to fade into lighter hues, rather than becoming clumpy and flaky, or difficult to apply consistently.
Not everyone may like this about this eyeliner, but I like that the black ink (BK01) is not overwhelmingly dark. I find it looks very natural for everyday use, but probably not the best for more dramatic looks.
I was disappointed to find out that Chic Choc recently raised its prices. One eyeliner pen costs NT$550, when it used to cost only NT$480, but I still think its worth it considering how long it lasts. Also, as I try to only buy from animal-friendly cosmetic companies, I was happy to confirm with Chic Choc's customer service that their policy is to never test on animals.
One downside I've noticed is that although the eyeliner is advertised as being waterproof, I find that the ink does sometimes smudge, so I probably wouldn't recommend this for people who want completely waterproof eyeliner.
If you're interested, you can find out where Chic Choc stores are located in Taiwan here. Unfortunately, I don't think Chic Choc has expanded to areas outside of Asia yet, but hopefully they will soon!