I took a couple of classes and worked at the office of a pretty big time professor while I was in undergrad/grad school. Working in his office, I got to look at some of his LOR's and found them to be pretty plain. Since I did have the honor of being an office-female dog, I think I'd get an extra line about that. Will his fame offset the vanilla-ness of the letter? I'll already be borderline at some schools and was hoping this was one soft factor that could help push me over.