I find this a very tough call to make myself. I have an Xbox 360 and Nintendo Wii and I love them both. The Xbox has some really great games and an extremely good online community. I also love the movies and arcade games available for download. It is also the only system to support Halo, which is one of the best combat games available. Xbox targets more mature audiences with more realistic and violent games. It also has built in CD and DVD players that allow you to watch movies and listen to music right from your Xbox.
Nintendo's main platforms, the Wii and the handheld DS, are both marvels in ingenuity. The DS folds easily down to the size of a wallet, but it has a crystal clear 64 bit backlit touch screen. The Wii uses cutting edge motion tracking and targeting technology to allow the user to physically move to interact with their environment. Its games are targeted for a more family environment, featuring the cleaner, more peaceful games. Its online capabilities are geared for privacy to protect children from outside predators. This also greatly limits its connection with the outside world.
Overall, I highly recommend sticking to Nintendo for a family environment, but going with an Xbox for more mature gamers. I think my Xbox is still my favorite system and it saved me from having to buy a CD player and DVD player. I still absolutely love my Wii and DS as well.
Every man dies, but few truly live. Live your life to its fullest, every day as if it were your last.