The 100L, and it is decent but not great for portraiture. For the same price, you can get the 135L which is probably the best portrait lens that's < $1500. The 85L is the best portrait lens under $5000 unless AF speed is more important for the situation than image quality. They don't call the 35L + 85L + 135L the "holy trinity" for nothing!
85 1.8 is a great lens and a bargain at its price (I'd say the 85 1.8, 135L and 17-40L are the best bargain Canon lenses), my only gripe is the color reproduction isn't on par with the 85L and 135L.
I second the opinion that the 70-200 is way too heavy, conspicuous and bulky for my shooting, but if i were getting paid for event photography, I would have to pick one up. The 70-200 f4 wouldn't be my first choice for portraiture since f4 doesn't really blur out the background enough for me (unless perhaps it's at 200mm).
Just my opinions of course.