I think salary figures from schools are somewhat overrated. Schools usually have a different makeup of career fields which their graduates go, and as a result, it's not always comparing apples to apples.
I don't know averse to debt you are, and I think I'd go to whichever school I liked more.
I think in most career fields, Cornell's name is worth $40k more than Wash U's. I'm not sure which I'd choose. I'm not a big fan of Ithaca and haven't ever been to Stl. In my personal case, I happened to choose the school that gave me more money, but I liked it there a lot more too, and made my decision primarily on fit, and not based on the companies that recruit there. Only time will tell if that's a good decision.
One other thing that strikes me as a little weird is that wash u decided to offer you money now. Does that mean that their yield this year is especially poor? I might be reading into things, but I don't know if it's a good sign that a school ups its offer after you say no to them.
Good luck.