Chemex FP-2 100
The whole thing with these filters is that they are thicker than most - this means that a lot of the coffee oils are held back by the filter, so you get a super-clean cup of coffee as a result.
The half circle filters come in packs of 100, and are suitable for 1-3 cup Chemex. These ones you have to fold yourself, so if you have a problem with that then possibly these are not the ones for you. It is easy to fold them though - there are even instructions on the back.