Best data transfer capabilities? Which Phone?

I am looking for the phone that has the best/fastest data transfer rates/capabilities. My sole internet source is through my phone plugged into my computer. I am trying to get the fastest connection possible. I had an LG that did pretty good a couple of years ago but now my razr is bringing up the rear. I am with AT&T but only need a phone that will work with their network. I figure I can unlock it if needed. Thanks to all.