I know it's a bit late for some of us northern gardeners, but if your soil hasn't frozen yet, you can still get some cloves of garlic in the ground this fall for a last-minute crop.
Garlic is easy to grow - just make sure you purchase clean seed stock, tested free of white rot, because once white rot occurs in a field, it is many decades before garlic or onions can be planted there again. So make sure that what you're planting is disease-free!
There are over 600 subvarieties of garlic! How to choose? Learn a bit about the different subtypes - the main types, hardneck and softneck, break down into subtypes.
Hardneck is the kind most small-scale producers and home gardeners grow, though in warmer climates especially, softneck garlic can grow well and easily. Don't forget to consider heirloom varieties; the ones that Slow Food USA has on their Ark of Taste are Lorz Italian and Inchelium Red, so that might be a good place to start!