For what its worth, here is my analysis...
I graduated from Wash U in 2002. From my experience, there are many good things as well as bad things associated with the school. If you are going to college for the sole purpose of getting your pre-med education and moving on, then I vote for ASU. If you want a more well rounded experience, go to Wash U. Let me explain...
First off, I got my ass handed to me as a premed. I was one of those kids that was fighting to just get above the mean on the exams. That translates to "fighting for a B-" which translates further to "2.7 gpa". Sure, there were times when I would do better and times when I would do worse. In the end, I was fighting a war which I did not handle well. Im currently taking Microbiology and Cell Biology at the University of Houston. Its a joke. I can study for an exam for 10 hours and get an "A" or study 5 hours and get by with a "B". At Wash U, it was more like study 20 hours for a "B" or 15 hours for a "C". Im just not that smart, relatively speaking. You have to realize that when you go to a school like Wash U, you will be encountering some of the most brilliant minds you will come across. Since everything (except physics) is on a curve, its tough to take out some of the top dogs so that you can achieve your "A". Can it be done? No doubt. However, you need to realize that your life outside of school will not be too exciting. I tried to have a life outside of school and it came back to bite me. Hard.
Therefore, if you are only concerned about the "premed" stuff, then go with ASU. I can assure you that you will find it much more bearable. At the same time, you will be saving a boatload of money that you can use on grad school. I will be paying around 300,000 over the next 4 years for grad school. I would have loved to have saved some money while in undergrad.
Now, if you want a great experience on top of the amazing education, go to Wash U. I have to say that although Wash U may have hurt my chances for getting into certain graduate school programs, I do not regret going there. The most important reason being that I had the time of my life with some of the kids there. With such a diverse student body (where else can you find a Jew, a persian, an egyptian, and an indian at a mexican restaurant?), you will encounter some of the most interesting people around. The faculty is awesome and are available for help any time you need it. Dont mean to go off topic, but is Sabotka still around? That guy was a weirdo. Anyways, the student life is great and your education will be second to none at Wash U. I wouldnt trade back any of my experiences for a higher gpa. In the end, I am still going where I want to go, but I have experienced things and developed friendships that I would not have had anywhere else.
Just be ready to sack up and study. Good luck.