Well...I don't know that I qualify as "having" kids, but I'm due the end of September and was faced with the exact same problem. I drove a '95 Ponitac Grand Am 2dr. My husband drives a '99 323 sedan. We decided that we needed to increase our hauling capacity, especially since both our parents live about 350 miles away and we'd be travelling with the baby plus all the "stuff".
We looked at the G35 and drove one just after it came out. It was a nice enough car, but what killed it for me was the lack of split folding rear seat. We were looking for a vehicle that we could use to carry odd shaped things, even without the baby in the car.
We seriously considered a Passat wagon. But, I just couldn't bring myself to pay over $30k for a new GLX when it would SERIOUSLY depreciate. (yes, looking used was an option, but you'll understand when you find out what we found!)
We decided to look at 5 series wagons. It turns out that around May '99, there was a SWEET lease deal (around $500/month, nothing down!) Now, 3 years later those vehicles are all coming off lease. We found a '99 TiAg/black sport package, sport seats!!, premium package, xenon, cell phone 528iT with _17136_ miles on it! It's still got about 11 months of bumper to bumper left on it. We paid $31800. We found it on Autotrader.com. It's in CT, but hey..we got to visit family and buy a car. We pick it up this Saturday!
Ok, that's my story, hope it helped some!
Joanne
P.S. Hey...Dr. Bimmer...if you're still reading this thread...the brochure you sent out was to my brother...I pick that up this weekend too!! Thank you VERY much!!