When I ran the employment numbers against cost of tuition and opportunity cost (for select schools in the top 40), the following popped up as best values (somewhat surprising):
Michigan
Rice
PT-Colorado
I think any decently ranked part time program has to have a reasonably high value, simply because you avoid opportunity cost. That said, depends on if a decent program is in your backyard. My boss went to Sloan part-time back in the day...an infinitely preferable option to the part time programs near my current city.
That said, any of the uber-elites take the cake in terms of value.