grey or black city

You can't go wrong with black, and you will inevitably want another one later, so you can address the color question then ;)
Having said this, I chose grey when I asked myself this same question, and am very happy with the choice... I've bought other black bags since but not a city yet, I guess I figure I can always get it later...
 
i like grey better! u can see the details better esp. from afar... both are good neutrals...there will be a very dark grey with green undertones called anthracite in the s/s 07 line that I am waiting to see IRL! :graucho:
 
Good question. Though I really like some grey tones (not sure which season's grey you would be after), I think black is a really nice classic Bbag color that you can wear with anything. So without knowing which grey you would be after, I'll say black.