Week 1 (WR): M. Williams (TB) or Dez Bryant?

[YOgun27]

I'm a little thin at WR this year, and will be starting Greg Jennings and Robert Meachem, so who should I start as a third WR? M. Williams or Dez Bryant? Williams has the more favorable matchup, but Dez might have more potential. I can't decide!
(I also have Nate Washington and Brian Hartline on the bench.)