I do somewhat miss the integrated factory nav system like I have in my G35 and the other things you get with the nav package (hard drive, ipod integration, more custom settings). I love the 40th color combo and don't regret my decision but I for one would have paid $1800 more for the car with nav. I don't understand why Nissan made the decision to not offer it in the US.
On a side note because there were a couple questions about it in this thread... my 40th came with both factory installed splash guards and illuminated kick plates. It had an MSRP of $40,000 exactly which I thought was kind of funny.