+1 vote for the Salomon Womens XT Wings 10+3 Vest. I've managed to fit a 2-litre Camelbak hydration bladder into the bladder compartment - other makes of bladder I think only a 1.5 litre would fit, because of the shape. Note it comes in two women's sizes - I have the S/M (teal) one.
Used it on a 50-miler with no problems. I love the fact that I've got two zipped front pockets and one zipped side pocket I can get at while running, for holding food, and the open-topped side pocket which I use for holding hat/gloves/tissues (it will expand to hold windproof jacket as well. Also the zipped inside pocket is great for valuables, while I keep stuff like a small bottle of Elete in the outside pocket on the back for quick access while refilling the hydration bladder.
I also have an OMM 12 litre, which isn't bad, but it's less organised (1 x pocket on waist belt, one pocket on the back (outside), bladder compartment, main compartment.