And if you have never been a customer of Baker Creek Heirloom Seeds, I suggest you order their catalog. It's vegetable porn for a Minnesota gardener in midwinter! They have expanded to a wide, 124 page format which includes gorgeous full page color photos of selected varieties. No centerfolds, though. ;)
I really admire Baker Creek's owner and founder, Jeremiath Gettle. At the age of 28, he has established a seed company that is willing to take on the Goliaths of the industry. He openly opposes genetically modified seeds, searches the world for traditional (but unique to many Americans) vegetable varieties, and hosts educational events at the company's headquarters near Mansfield, Missouri. I hope to make it there for one of their festivals some day.
But if you're not into full color vegetable porn and prefer to just read about things, I suggest Fedco Seeds. They are another company that has pledged to not buy from companies that offer genetically modified seeds. Their catalog is in plain black and white, a few lovely illustrations but no glossy photos, and if you're my age or higher you may need to invest in reading glasses to read the small type. But they offer excellent seed varieties along with some witty commentary.