Ball Head for D90 and 70-300vr

I have pretty much decided on the Manfrotto 055xprob legs but there are so many heads to consider, Which one would be suitable for my D90 and 70-300vr.What do you think about the 322RC2 horizontal grip?
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Nikon D90, 18-105vr, 70-300vr, Velocity 7x
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