As far as I know, all willows are messy, because they shade out their own inner branches and then they die and fall to the ground. I have a large weeping willow (either a Wisconsin or a Niobe, I can't remember) that I planted as a 6' bare root tree. It grows extremely fast but of course is weak wooded. Every spring and after every storm I go out and pick up the branches. I also have to give it a hair cut 2 or 3 times a year so I can mow under it. And it has shallow surface roots that make mowing under it a challenge. But I still like it, and by a lake shore is a good place for one. I would buy a bare root one in the spring and plant it yourself. That is the cheapest way to go unless you just start one from a cutting, and willows are pretty easy to transplant. Be careful what you buy - some willows don't weep. River birch might be another option, but they are messy too.

You might try a burr oak, they are often near waterways and can grow over 100' tall with 10' thick trunks!

Also, perhaps a Hovenia dulcis:
Hovenia dulcis is relatively rare, typically found in the stream-irrigated valleys
http://en.wikipedia.org/wiki/Hovenia_dulcis#Reforestation

Here is a link that might be useful: Burr Oak

Any of the red maple cultivars would look great.

Oaks and maples wouldn't be great if you're looking for a tree that doesn't drop thick leaves (unless you're down south which means some oaks will keep their leaves year round). I think the dawn redwood is a no-brainer in your situation. These trees grow very rapidly and can grow to massive size (200+ feet high!). They have needles that turn red and then drop in the fall, so it wont be dropping messy leaves but you still get the bonus of fall color. Also, these things love water. They can even grow in standing water, so they would love being planted by a lake. These aren't super common in the US because they weren't introduced here until the 1940's, so you'll have a pretty unique tree as well. You'll see I attached a picture of one, and you won't believe that massive thing is only about 50 years old! Talk about rapid growth. Finally, these are considered critically endangered, so you can feel good about planting one.

WOW! Thank you for all the help everyone! So many great choices! I will sit down now and try to decide which way to go! Might even try planting a few different recommendations throughout the yard! Thank you again for all your help!

Nyssa sylvatica would be another one worth considering. They are common around lakes here in Ohio and they look nice year round, and really red in the fall. It is not fast growing like a willow, but most noble trees are not.

Wow, so what's a good source for Dawn Redwood (Metasequoia glyptostroboides) seeds or seedlings?

Here is a link that might be useful: Dawn Redwood

Metasequoia is the neatest thing since slided bread in my opinion.

I have mailordered them with very good success. Think all 100 of 100 I got bare root from Musser for the giveaway leafed out at least. Arbor Day Foundation actually sent me a live one which has done me well (1st tree I ever planted lol). Forest farm is a reputable company that has shipped me good metasequoias and their yellow cultavar Ogon. They are a bit more expensive though but well packed.

I think we are too far into the year for best mail order success though. I got my Arbor Day tree in November and that worked well. Wait till fall if you have to mailorder.

Bald cypress is a similar tree. Those will grow right in swamps however they get started. I would love having some dawn redwoods right next to bald cypress for comparison like the Missouri Botanical Gardens does.

Or what about a few Loblolly Bay (Gordonia lasianthus) flowering evergreen trees?

can grow to 70 ft (21 m) in height with trunk diameter up to 1.5 ft (0.5 m). It has persistent, leathery oblong leaves 4-6 in (10-15 cm) long that are dark green above and paler, sometimes woolly below. The large handsome flowers are about 3 in (7.6 cm) in diameter and appear in late spring and sporadically throughout the summer. The white blossoms are composed of 5 petals that burst from a spherical bud and surround a golden center. The flowers are fragrant
Likes moisture and can tolerate swampy conditions.
With its handsome evergreen foliage and showy blossoms, loblolly bay makes an excellent specimen tree or grove in wet areas and at the margins of lakes and ponds.
It's the beautiful flowers that make this one of my favorite native trees (that and the fact I live surrounded by swamp). Three narrow spires of loblolly bay tower over my pond. Throughout most of the summer it launches its large but delicate white flowers into the water.

Here is a link that might be useful: Loblolly Bay