There are strongly differing opinions and personal experiences regarding the card speeds. I encourage running your own tests, in your real-world shooting conditions. It really doesn't matter what i think, or what someone else thinks, is the optimum card for the D7000. It's what works best for YOU.
Beg, borrow, or buy some different cards and test them yourself. Costco and a few other stores have a no-question-asked return policy that might help. You can also buy 8GB cards at a reasonable cost before investing in big ones.