If your main interests are political economy and social movements within a Marxist framework, I'd look into the following programs in this order:
1. NYU: From speaking to folks in the program, it looks like the best program for Marxists.There are faculty members like Vivek Chibber as well as a number of grad students who do related work. The downside is it's a really hard program to get into.
2. Wisconsin: This should be fairly obvious because Erik Olin Wright is there. However, I hear NYU would probably still be better in terms of training. Again, really hard to get into.
3. UC-Berkeley
4. Johns Hopkins
I have similar interests but I'm also interested in development. I wasn't able to get into NYU, Wisconsin or Johns Hopkins (didn't apply to Berkeley).