k&n
k&n are post-oiled, d'oh!
I've usually ran uni or twin air, but have been in a pinch on more than one occaison and bought/ran a pre oiled job. recently I tried a k&n and was very impressed with how well it performed in dusty and sandy conditions both. i found the k&n easier and less messy to clean and re-oil than its foam element counter-parts.
(i've tried like 3 brands of pre-oiled filters, the ones i have used have been inferior in quality to uni/twin air)