Nonpareil. They're about $15AUD in Australia, and if you're crazy enough to pay that with the dollar being as great as it is at the moment, you can pick them up at Priceline or online at the Prestige website.
What I like about them is that they dry quickly and don't smudge. They don't have that ironclad grip that the UD 24/7s do, but they do have pretty good staying power. They're not waterproof though, so don't wear them if you're going to see a sad movie, or your boyfriend is taking you out to dinner to dump you.
The colours that I have are Fearless Teal - which is actually more of a forest green, and Powerful Purple - a blackened purple. I find that both of these colours really enhance my eye colour (green).
These are very soft and require frequent sharpening - another good reason to buy them cheap at Nonpareil rather than pay three times the price here. Overall, I like them, and were I not practicing No Buy Month in October, I'd be tempted to pick up a few more.
EDITED TO ADD: I should have mentioned that I don't generally use eyeliners on my water line; for some reason in the last couple of years it's been annoyingly ticklish. The tickling makes my eyes water, which makes it too hard to smoothly apply the liner. However, in the interests of research (and because Su asked about it), I've given it a go. It does apply quite well (annoying tickling notwithstanding), and seems to be holding up. However, as I said earlier it's not waterproof, so if you've got watery eyes for any reason, this is going to smudge like the dickins.