First, some background! Spinach first came from Asia, but it is now grown pretty much everywhere since it is so good for you. I grow spinach yearly in my garden, and it is very easy to grow. Even if you've got a container garden on your porch or at your window, give it a try! You can have fresh daily greens without any effort.
Iron
Normally most people get their iron from meat. For vegetables, many vegetables provide about 10% of iron per serving. Spinach gives you about 20% per serving. So yes, it is better than other veggies, but still not as good as meat or other high-protein items. Your body gets less iron from cooked spinach.
Calcium
When you think of calcium, you probably think of milk. Spinach provides about 6% of your daily calcium. Not a huge amount - but still there. You get much more calcium from collard greens - more in the 70% range.
Other Vitamins
Spinach has 25% of your vitamin C, 70% of your Vitamin A, and 5g of fiber. You also get a TON of Vitamin K - over 300%.
Oxalates and Phytates
With all these great things, it's important to understand something about spinach nutrition. Spinach - and some other vegetables - have oxalates and phytates in them. Think of oxalate as an iron and calcium magnet. When you eat oxalates, they grab onto iron and calcium and drag it out of your system. So it's sort of ironic that a food high in iron and calcium also has oxalates in it!
To counteract this, you want to take your spinach with vinegar or Vitamin C (or both). These help your body better counteract oxalates. You'll note that spinach does have some vitamin C in it - but more is better.
Folates
Folates - vitamin B9 - are very important to your health. Spinach has about a full day's supply of folates in a serving. However, if you boil spinach even for 4 minutes, you lose about half of those.
Cooking Options
Boiling spinach loses half of the folates, and any cooking reduces iron. Eating spinach with vinegar highly increases calcium absorption. Cooking food does seem to slightly reduce the power of oxalates and phytates - but it seems that this effect is not enough to offset the "damage" done by cooking. So in general, to get the most benefit from spinach, it's good to eat it fresh and raw, with vinegar and something containing vitamin C. Bell peppers, brussel sprouts, and broccoli all give you over 100%!
Enjoy in a fresh salad!
Lisa Shea's Library of Low Carb Books
