My vote would be the M's K&N. - All the benefits of a cotton filter, but much bigger (so more filtration over a bigger area).
As above though; the benefit is really only if the airflow is genuinely restricted. - Oiled filters tend to coat the internals of the MAF, foam filters tend to degrade (and drop bits in the engine; ever wondered why HKS sell replacement elements?), mesh flows better... because it doesn't filter as well, cotton filters better... but doesn't flow as well.
Interestingly many of them tell you to resist cleaning the filter unless it's absolutely filthy; the more dirt that's trapped, the better it does at catching more dirt (since the pore sizes decrease).