I love acers , misdee - loads of varieties, none of them very tall, very pretty leaves. I have the one at the top, it says it grows up to 6m but mine is planted in a small bed surrounded by concrete and after over 10 years (can't remember exactly) it's only about 10'.
They are really lovely and the leaf colour changes throughout the year, from pale yellowish green in spring through darker shades of green to orange in the autumn, and if it is a sunny summer and a frosty autumn they turn brilliant fiery red.
Let me know what size of tree you are thinking & where you live & I'll ask DH who is a qualified 'tree' person. Do you want nice leaves, nice colour, shade etc. Do you want to plant a bigger tree or happy to go for something small & watch it grow ?
do you have a budget, as horse chestnuts/sycamores can be grown from seed and grow very quickly and look lovely when grown, put it this way a sycamore can reach a height of over 10 feet in 3 years and grow over 30 feet tall.....if you like blossom the prunus variety are spectacular, cherry blossom etc..
DH suggested a birch - silver or himalayan. Or a Whitebeam. Acers are gorgeous - beautiful colours, but are expensive if you want a big one. If you go for a tree with berries - avoid the ones that are poisonous, with children around.