My kids used to get along ok, but they each had their own circle of friends and generally preferred playing with their friends over hanging out with each other.
Since we moved to a more rural area, they've truly become best friends and love to play with each other! It makes our lives a lot easier, since they can entertain each other for hours. Plus it just warms my heart to see them being so close to each other. Don't get me wrong: there are plenty of fights and arguments, and they're not always joined at the hip. But all in all, they're a lot closer than they used to be!
How do your kids get along these days?