"Herb" of the Day: Leeks

I've always loved leeks, those tall, graceful, green relatives of the onion with a sometimes outrageously thick stem. These days, I've bought them frequently at our local Farmers' Market. But today I just purchased a pot of leek starts, and so hope to grow my own crop of the svelte, white-footed alliums.
Mind, until recently I'd only known leeks in their truncated form, lying butchered for purchase on market shelves. It wasn't until I started gardening that I knew what a leek in full flower looked like. And they're gorgeous!

These leeks in the backyard garden I share with a friend show the round flower heads of a delicate purple color, resembling oversized garlic or onion blooms.
Besides a giant pretty stem, why grow leeks? Or for that matter, eat them? Like all alliums, they're good for boosting immunity to nasty things like cold and 'flu. Leeks are wonderful in soups and stews, but can also be added raw to salads so as to get their full health benefits (i.e. vitamin C is destroyed by heat), yet without quite the raging kick of raw onion or garlic. A cup of raw leeks (although this is more than most people may wish to eat at once!) supply half the RDA of vitamin K, and are also rich in vitamins A and C, plus 10 percent each of your daily vitamin B6 and iron. Then there's that cute way a leek parses itself out into handy little bite-sized rings when you slice it.... if you like a bit of fresh green spice and are all right with alliums, what's not to like?
I'm already wondering how big my leeks will get; I'd better give them lots of room.