Usually a #8 yellow, maybe a #12 yellow, occasionally a "light" red (B&W equivalent of a 23A as opposed to #25), maybe a light yellow-green (#11 equivalent). Polarizer alone or in combination with the others depending on the situation. I keep a 3-stop ND filter in my kit for the occasional time when I want to drag the exposure a bit. Would like a heavier ND, say 10 stops, for really dragging water or giving water some softer effect in broad daylight. I've found my taste in sky filtration to have lightened a bit over time. I think the haze of distance is a good thing in many instances.