Provided that financially you can afford to go to either, then I would say to forget about the fellowship and judge the schools for themselves.
The question is simply which program is the best for you. This includes how many professors are doing good work in your areas of interest, rankings of the program etc. If one program is clearly better than the other, then go with that if you can afford it. Otherwise, if either one would be great, then go with the fellowship. You need to investigate the work of these other professors. Bearing in mind that you may not get along with one or two of them, are there other faculty you could work with?
I am inclined to think that future opportunites would not come from you having received a fellowship, but from you having completed a very successful PhD at a top institution. When it comes down to it, you make your opportunities by working hard and achieving results. So like someone said earlier, go to the place where you can produce the best work, most likely the one with the best academic support.
