The 16-85 VRII Nikkor is a lovely lens and goes well with the D7k but isn't as quick as the 17-55. You can pick up a 16-8 for around £320 on here second hand.
I always think 55mm isn't long enough for a walk about lens, or for some portrait work. I'd get the 16-85, 35mm f1.8 and the 85mm...