Some Seed Companies To Consider

I haven't used all of these seed vendors yet, but I sure like to look at their catalogs. I am NOT listing them as an endorsement, but rather as a convenient starting point to shop for seeds and gardening supplies. This is America, so "buyer beware."

100% CERTIFIED ORGANIC:
Abundant Life Seed Co.
FEDCO Seeds
High Mowing Organic Seeds
Natural Gardening
Seeds of Change
Wild Garden Seed
Wood Prairie Farm

OPEN-POLLINATED and/or HEIRLOOM VARIETIES:
Adaptive Seeds
Amishland Heirloom Seeds
Baker Creek Heirloom Seeds (best Melon selection I've seen)
Botanical Interests
Bountiful Gardens
Comstock, Ferre & Co.
D. Landreth Seed Co.
Heirloom Acres
Heritage Harvest
Native Seeds/S·E·A·R·C·H (Native & Southwest specialists)
New Hope Seed Co.
Renee's Garden
Sand Hill Preservation Center (Heirlooms, plus Heritage Poultry)
Seed Savers Exchange (superb)
Skyfire Garden Seeds
Southern Exposure
Sustainable Seed Co.
Turtle Tree Seeds
Victory Seeds

TOMATOES (mostly):
Appalachian Seeds
Marianna's Heirloom Seeds
Tatiana's TOMATObase
Tomato Growers Supply Co.
Totally Tomatoes

SINGLE FOCUS, NON-TOMATO:
The Chile Pepper Institute of New Mexico State University
Filaree Farm Organic Seed Garlic
Fungi Perfecti
The Garlic Store
Gourmet Garlic Gardens
The Pepper Gal
Potato Garden (Ronnigers + Milk Ranch joined together)
We Grow Garlic

HERBS:
Horizon Herbs
Pantry Garden Herbs
Richters (extremely informative catalog)
Sand Mountain Herbs
Thyme Garden Herb Co.

SPECIAL FOCUS:
Cook's Garden (Chef focused)
Evergreen Seeds (Asian varieties)
Gourmet Seeds International (Chef focused)
Kitazawa Seed Co. (Asian varieties)
The Kusa Seed Society (Grains)
The Maine Potato Lady (Potatoes, onions, etc.)
Old House Gardens (Heirloom Flower Bulbs)
The Sample Seed Shop (sample sized packets)
Seeds from Italy (Italian varieties; Franchi Sementi distributor)
Select Seeds Antique Flowers (Antique or Heirloom Flowers)
Sunrise Seeds (Unusual Varieties)
Trade Winds Fruit (Fruits & Tropicals)

SPECIALISTS IN REGIONALLY ADAPTED VARIETIES:
Adaptive Seeds (Northwest)
Native Seeds/S·E·A·R·C·H (Southwest)
Plants of the Southwest (Southwest)
Seeds for the South (South)
Wood Prairie Farm (Northeast)
Victory Seeds (Northwest)

NURSERIES (Trees, Bushes, & Plants, mostly):
Crimson Sage Medicinal Plants Nursery
Eden Organic Nursery Services
Logee's Tropical Plants
One Green World
Raintree Nursery
Stark Bros.

GENERAL SEEDS / SEEDS & SUPPLIES (some have nurseries, too):
Irish Eyes Garden Seeds (large Potato selection)
Johnny's Selected Seeds
John Scheeper's Kitchen Garden Seeds
New England Seed
Nichols Garden Nursery
Peaceful Valley Seeds (Organic supplies)
Pinetree Garden
Redwood City Seed Co. (large Pepper selection)
R. H. Shumway's
Seedman
Thompson & Morgan

I have shopped from Baker Creek, Gourmet Seed, Irish Eyes, Kitchen Garden, Kitazawa, Pinetree Gardens, Richter's, Seeds from Italy, Seeds of Change, and Seed Savers Exchange and have had only positive experiences with each one of them.