@knownow re: Penn Wharton BS in Econ vs CAS BA Econ. Do not be fooled by the BS in Econ title of the Wharton degree, this is a business degree not an economics degree. The traditional economics degree is offered through CAS. Wharton has a BEPP concentration that is essentially a watered-down version of the traditional econ offered at CAS and is usually picked as a secondary concentration by Wharton kids.
Now you can still take many classes both at Wharton and CAS regardless of your major, but if your goal is Phd the traditional Econ major through CAS would serve you better because it will be more quant heavy and will give you the skills Phd programs are looking for. Or if you want to do Wharton but are still thinking of PhD make sure to supplement your curriculum with traditional Econ courses as well.
Now back to your original question, the tippy top economics schools have traditionally been Harvard and MIT. Stanford was getting a lot of buzz that it was rapidly catching up to those two, but not sure if it is actually considered exactly on par at this point. Probably not, but it is a close third.