I suppose TMAX 400 would be a great choice with so many recommendations, I am intrigued with acros as well since I will just be doing star trails and not actual tracking (yet) I'd have to also buy a tracking tripod head that could hold a 4x5 camera. that would be really great for getting the milky way with some color film, id suspect velvia 50 would be good for that since the night sky doesnt have terribly much contrast other than the stars themselves which id want to "pop" anyways.
I do really want to know what film Xkaes used for his star trail shots. I've heard that color film can suffer from color shifts with long exposures that require filters to correct it or lots of work in post either in the dark room or digital editing.
Would anyone recommend Ektar 100 since it has a pretty full proof dynamic range? I'm not sure how it reacts with long 10-15min exposures so input on that and any other possible color films would be good as well. I'm looking to buy two boxes on this trip, one color and one B&W and would like relative utilitarianism from one of them or both.