Cool - let me know. For what it's worth, I looked at 2006-2008 M5s when I was buying this car. I opted for the 2008 because it has the LCI package. Also, the earlier years had some expensive issues with the Vanos pump that got sorted about halfway through 2007.
For details on the LCI updates, check here: http://5series.net/info/2008_LCI_Detailed_Changes.pdf
Oh, and congratulations on the little one! Trust me when I say that $7k doesn't buy as many diapers as you might think