I agree the Nav option is overpriced these days, but you do get more than Nav - you get the Music Box, you get better iPod/CF control, you get better settings control, nicer environmental settings display, another trip computer, and GPS Nav. The integration is very nice, though sometimes I wish I had the nicer 2010 display - the 2009 display is a little sad compared to my iStuff.
And once I install my NavTool/backup cam, the Nav will be even nicer