Dogwood would be great for the spring as would redbud but if you have sunlight imagine driving up the lane with crapes in bloom, now that's what I call a drive.

Here is a link that might be useful: Propagating Perennials

Redbud and Crapes are also two I have in consideration. I'm even considering alternating White/Pink or red in the color scheme. I am also going to install a nice split rail entrance to the drive way and may extend that fence up the drive at a later date. So many decisions to make :-)

Is it full sun or part shade? Hawthorns ('Winter King' is one cultivar) provide a similar form (upright) to ornamental pears. Crabapples will be wide and spreading.

Crape myrtles are quite overused. Dogwoods, as a native understory tree, are another story and always quite beautiful, but they do best with some shade in the afternoon. If you do redbuds, consider getting the 'Forest Pansy' or another cultivar. I find they have a lot fewer seedlings than the species.

I'm full sun. And it does get hot out here in the summer!

Me again mentioning the birds :-) Same as last tree post.

Bradford Pears is a tree that provides no food and they are rather fragile from what I've been told. Dogwoods are lovely for sure at a time of year when we're coming out of winter so extra beautiful. I favor crabapples because of the food supply for wildlife. I find that in putting plenty of things around for them to eat, we never have what people call "nuisance wildlife" because they don't have to be bad from hunger. :-)

Here's a post from another GardenWeb forum on crabapples.

Here is a link that might be useful: Crabapples for birds

Native hawthorns are an underused native tree that also provide food for wildlife. They do have an upright form and would do great with full sun.

Crabapples would too but they do have more of a wide than tall shape.

Serviceberries (Amelanchier species) are also good for birds (they love them), but have more of a loose shape than a formal one. They can have beautiful fall color, however, making them a multi-season tree.

Dogwoods would not be as pretty in full sun and would have a hard time in times of no rain.

Do the kousa dogwoods do better with more sun? Because dogwood berries are a favorite with the birds.

I think if it were me, I'd mix 4 or 5 types of trees to allow for diversity and a variance in the look, as well as disease resistance, rather than just 1 or 2 kinds. You could do it symmetrically across the drive, or clump the trees randomly, more like nature.

Did anyone mention vitex? That would be another colorful one.

I think Kousa dogwoods can tolerate more sun than the natives. Cornelian cherry likes sun too. Vitex are lovely. Prunus mume are beautiful in bloom and very fragrant in Jan.- Feb., although I wouldn't use them for mass plantings.

What about the Yoshino flowering cherry? I've seen them in mass plantings and they are spectacular. Plus, since they spread wide you wouldn't need to plant so many to achieve the full look. Also consider the deciduous magnolias. They are quite spectacular in the spring, as well.
---Keith

Or perhaps one of the 'smaller' cultivars of the southern magnolia. Wish i had room for one. Or what about a star magnolia? They are gorgeous in spring. I have a cornelian cherry, and i like it. More of a bush shape than upright tree, but it does get berries that birds and people can eat.

What about the Yoshino flowering cherry? I've seen them in mass plantings and they are spectacular. Plus, since they spread wide you wouldn't need to plant so many to achieve the full look. Also consider the deciduous magnolias. They are quite spectacular in the spring, as well.
---Keith

What about a "weeping" tree? They are always beautiful.

When she posted about the yoshino i thought about a weeping cheery. Or a weeping blue spruce- those are gorgeous. Ooh- come to think of it i really love the form on the deoder cedars as well- not weeping or super upright, but very graceful. Wish i had room & light to grow one. Another interesting tree form wise is eucalyptus. they will get freeze killed to the ground or trunk every so often, but they grow back fast, and those blue round leaves are inimitable.