Yes this afghan is quick and easy to make and so soft and warm, no matter what yarn you use. The colors are up to you, you can use all one color way in different shades, you can use a variety of yarn colors. I personally think that there is no color combination that would look horrible, it all seems to work out beautifully. You can see in the photo (although the lighting isn't great) that the afghans are different in the colors I used but both turned out awesome.
size 35, 40 inch circular needle (yes size 35)
600 yards each of 5 different yarns. I used primarily dk and worsted weight but I think a fingering weight or variegated sock weight yarn would be beautiful in the mix, or a really soft chunky yarn, as long as you have 600 yards of each.
Cast on 60 stitches using all 5 yarns knit together
Knit (K) 3 rows
Row 4: K3, Purl to last three stitches, K3
Row 5: K
Repeat rows 4 and 5, for as long as you like. Leave enough yarn to knit three rows at the end. And then bind off. Work in ends.
My afghans turned out to be about 50 inches by 70 inches. But you could make a smaller afghan or a larger one easily by adding more or less yarn. You could use up all your scrap yarn, when one runs out just tie on another yarn and keep going.
I found that 5 yarns knit together was the key for me. Less than 5 and it was a little too thin.