As one of the few film guys around here..... I'm currently using Fuji Provia 100 as my "if I could only have one film" choice. I normally use Velvia 50 (soon to be 100 I guess - I have a lot of 50 sitting here) outdoors around water. I think it works well because of the higher UV near the water. If in doubt, or late in the day, or near warm-colored rocks or buildings, I would use the Provia. BTW, Astia used to be my film of choice until I got blindsided by color shift they did last year. Before that, I used Kodachrome 64 for late sun and studio. I personally would not use anything 400 ISO unless I really needed the speed for something. I need for my images to be as grainless as possible because I do calendars and posters from them. For what its worth, Playboy uses mostly Kodak products, last I heard it was usually Ektachrome Professional (slightly warmer) or just good old Ektachrome Daylight. I think they tested (and some guys used) the E100 films but I personally think they have some odd color bias' in them and would only use the for effect.
Remember though, that in glamour or fashion, its OK to break the rules. You should experiment to find what you like for certain situations or assignments. I did this shoot of Roxanne Galla at sunset on Ektachrome 160 Tungsten (pushed one or two stops) a few years ago. I was testing - I figured if the light at sunset gets very warm - like tungsten - it can't be that far off.
Andy Pearlman Studio