ELF's liquid liner is great for beginners, much better than the Fashion 21 liquid liner (the waterproof kind) The ELF liquid liner brush is short, so you have more control over it.
Staying power is not a problem, either. I had it on for nine hours yesterday--it didn't budge. Plus, it's cheap! The only problem is that you need to do several coats to get a really black color, and it takes a while to dry. Other than that, it's great.
I really want to try gel liners next.
I've heard good things about the Kiss Me Heavy Rotation gel liner.