Like others have said above the current Passat is an amazing car. It fits 4 people comfortably and is decently roomy. The A4 and BMW 3 series are too small to take rear seat passengers comfortably. You could get the BMW 525 or 530 though.
The current Maxima, as good as it is, sits in the shadow of the cheaper Altima. The Altima has a much better chassis, same engine (with 15 less hp only), and I believe is about the same size. Expect something special within a year or two from Nissan for the Maxima. That either means you'll get a wicked deal on a new one now, or you'll feel sorry in a year that you got the current one
For your purposes, at the lower end, I like the Passat. My dad owns a 2001 1.8T and it's been great! I drive a 97 Jetta and it's been awesome as well. Higher end, I like the BMW 530i, but that's not a car for everybody. You have to appreciate something like that to justify the cost.
"it's kind of like an Airbus, it's an engineering marvel, but there's no sense of passion" -- J. Clarkson re: Coxster