For me, it’s the weeping willow.
Out in the front yard with a big, old house behind it. No other trees around. Just a solitary, lonely figure with big drooping branches reaching groundward. It would seem to suggest a hint of sadness but I see instead strength and solitude.
Sure wish I had one.
I like apple trees, mainly because they attract wasps who then sting trespassers.
egg (hates nature)
I like nice stands of pine. The smell is just fantastic.
I like 200 year old oaks. 
They are so wise.
“One could do worse than be a swinger of birches” ~ Robert Frost
Pine trees are the best for smell but I’ve always found Maple trees are better for climbing and their leaves are beautiful in the fall. Weeping willows are fun to hide under. For some reason I really dislike Scotch pines. I think it’s the only tree I wouldn’t have in my yard.
Giant Sequoias are pretty awesome. They’re popular ornamentals here in the Pacific Northwest. The most massive living organism on the planet is a General Sherman in Sequoia National Park.
I thought it was the Great Barrier Reef.
The larch.
The. Larch.
I like Italian Cypress trees.
It’s the first one that pops to mind. I love trees in all shapes and sizes, but cypress is the first one I thought of.
Mimosa
Their fuzzy pink blooms smell so nice, and the bark is nice and smooth so you don’t hurt yourself climbing them.
Coconut palm. Picturesque and tasty.
I think it would have to be the Loquat or Japanese Medlar (Eriobotryia Japonica) - It has fantastic architectural foliage and the fruit is heavenly.
But there are so many nice trees, its really hard to choose.
Hard to pick just one, but my vote goes to the madrona, also called the Pacific madrone. The papery bark peels off, leaving a perfectly smooth, deep brownish-red trunk. Provides nice contrast to all the conifers we have here in the Pacific Northwest.
Hmm. I had heard that is was a mycorhizzal fungus somewhere in Minnesota. IIRC, it was estimated to cover quite a few acres and weigh several hundred tons.
My pick would be a Japanese maple. In the fall, the leaves turn a brilliant scarlet which contrasts beautifully with the yellow leaves that turn. Autumn is a beautiful season in the East and the horrible summer is worth suffering through to enjoy such beauty.
Hmmm. As a common tree, I like chesnut-trees a lot. Less common and very different : the cedar-trees.
And for a garden definitely a cherry-tree. The Japanese are right : there’s nothing like a cherry-tree at spring (and you can graft it with an ornemental cherry-tree, and get a tree with bicolor flowers). Plus, obviously cherries are delicious. And children like climbing on them (essentially when there are cherries).
OK, I just looked this up and here’s what I found:
I’m also somewhat fascinated by olive-tree because they provide so useful fruits and some of them are so old…Planted by the romans, and they’re still doing their job of providing us with fruits and oil. Plus they’re a symbol of peace.
I was about to list some others, but actually it wouldn’t end. I just love trees. I like being below them, or touching them. they’re sort of a symbol of life and wisdom.
I don’t like pine-trees and the like, though : too regular-shaped, and always the same all around the year…Tree foilage has to become brown, and yellow, and red in automn. Pines and fir-trees are just arrogant, unoriginal and hollier-than-you trees.
I like maples, but particularly Norweigan Maples. The tree and the leaves get so much bigger than other maples. We had two in the yard when I was growing up. They gave alot of shade, and the whirly birds were fun to play with. The leaves turned a perfect reddish-orange and there was always enough to make huge piles to jump into.