One of the very interesting things about knitting is how it is an ethnic tradition in many different areas of the world. Twisted-Stitch Knitting devotes detailed attention to knitting in a particular area of Austria – it's an incredible stitch resource.
Mostly Mittens is a redo of a wonderful mitten book – tons of mittens in two-color work – mostly Russian designs. Another terrific resource – and mittens are so useful, fairly quick to make and these kinds of patterns look so impressive (but aren't that hard to make – really!).
These are just a few – it's a great time to browse and maybe get something warm going on the needles!