Around the fringe of a swamp: (this is for my area but you can look up which will work for you)

Coast Redwoods
Sequoias
Western Red Cedars of many varieties (but they don't like standing water for long)
Shore Pine (Pinus contorta var contorta)
Leylands
Blue Atlas Cedars
Gingkos
Red Horsechestnuts
Purple Robed Locust (Robinia 'Purple Robe')
Giant Dogwood (Cornus controversa)
Quaking Aspen
Catalpa
Sugar Maple
Raywood Ash
Green Ash
Nellie R Stevens Hollies
Himalayan White Birch
Japanese Maples
Quercus virginiana
Quercus myrsinifolia

In the swamp: (6-11" pooling water in winter)

WILLOWS -- Prairie Cascade Willow -- awesome, truly amazing tree
Babylonica Weeping Willow
Curly Willows
Blue Arctic Willows
Rosemary Willows
Nishiki Dappled Willows
Red Barked Willow (Salix alba 'Chermesina')
Violet Willow (Salix daphnoides)
Lapland Willow (Salix lapponum)
Bay Laurel Willow (Salix pentandra)
Swamp Tupelo (Nyssa aquatica)
American Sycamore Buttonwood (Platanus acerifolia 'Bloodgood')
London Plane Tree (Platanus occidentalis)
Sweetgum
Black Cottonwood
Bald Cypress
Blueberries
2 kinds of swamp Eucalyptus
Swamp White Oak
Swamp Red Maple
Swamp Magnolia
River Birch
Alder

Willow and alder would be my recommendation!
Great list in the post above!
Good luck, and let us know what you decide.

Josh

Certainly bald cypress (Taxodium distichum) would work. It's a beautiful deciduous conifer tree that is native to much of the eastern US.

Here is a link that might be useful: Taxodium distichum

I'm with greenman, heckuva a list.

Don't forget the tamarack-American larch. Well adapted to high water tables and needs full sun.

+oM

Swamp White Oak (Quercus bicolor).

Thanks. I'm in a swamp and have planted all those trees except Alder. Planted a lot more but some didn't survive the water. Over 300+ trees in here, an experiment to see what can handle the water. In the summer I have to water a lot because the underground springs go dry and these trees want a lot of water and are trying to establish. 2 years 3 months since first 200 planted.

The thujas are doing really well. They were straggly and leaderless when planted so their progress has been wonderful. The dawn redwoods are happy. The Prairie Cascade willows are spectacular, bright golden and growing so fast it's astounding.

http://s202.photobucket.com/albums/aa127/Cascadians/
you can view my baby swamp trees here