[FONT="Comic Sans MS"][COLOR="#300090"]I started by learning crochet sometime around the age of 12; it was a hat and scarf set using a double ended hook in fact (but that's for another story). My mom also taught me to knit and purl; my swatch used a red acrylic yarn in worsted weight (I don't think I ever finished it off and it is now lost or recycled).
The advantages of crochet make it the better choice for large projects like blankets (or afghans). You can set it down and pick it back up at any time (event stuff it out of sight in a bag if you need) and with little thought to losing stitches. If you do lose a stitch or several they are super easy to see and redo.
For speed and size, I'd use a double crochet (dc) stitch and a simple zigzag pattern. It will give you fast results and a visually interesting FO. You can use a variegated color through out or choose several complementary colors and make it striped or banded (think like the Dr. Who scarf).
What is the total width and length of your project? You may want to plan way ahead on this. My mom made an afghan for each of her children as high school graduation presents. I'm the youngest of six and in my forties and all of us still have our afghans! (Don't you know all our spouses requested their own afghans too!)
Wave or ripple (or chevron) they go zigzag across the width /\/\/\/\/ or up and down the length. You can make your own pattern or find one in a book or on the Internet. (I didn't stop to check any that the others have posted, but I'm sure they are all good.)
Good luck and happy hooking! Crossed Fingers