Looking for the perfect tree

Have a very large *outback* which have
flowers that are mainly in the border of
the yard, was thinking of a tree in
the center of the yard as a focal point
and work from there. I was thinking of
a weeping willow. I don't want a
flowering tree, I like my flowers to
put on the color show, just want something
that wont overpower the yard but add to
my existing flowers, my colors are
pinks, purples and lavenders and a few
yellows. thanks