Congratulations Dan!

We got through most of our son's first 4 years with a Golf as the family car, and it didn't put us off from long roadtrips. That being said, I'm 5'10" which is about the limit of comfort for the passenger when you have a car seat in the rear. We still managed to pack enough gear in the Golf to go on week long camping trips too.

My wife recently replaced her MX3 with a Mazda6 Sports Wagon which is a fun car. Handles very nicely, and is larger, although so far in 2000 miles it's only managed 19.2mpg (80% highway miles - supposed to get 21 city, 26 highway IIRC.)
I'd also recommend checking out the Passat. At this point it's issues are well known.

Both the Mazda6 and the Passat will need a gizmo to add an auxillary input to their stereos. Both have physical mounting issues wrt an empeg. Bear in mind that your new car is going to be the one that you end up using on long family roadtrips; Thanksgiving, Christmas, vacations etc., so this might become an issue (I think my wife may end up with a Karma for Christmas).