Anything will work really, whethrer knit or crochet. The needle size depends on the yarn, but if you use a medium thickness yarn and larger needles it doesn't take as long. The problem with a scarf for a first project is that it can take a long time and gets boring so you need something to keep your interest, whether it's learning new stitches or varigated yarn.
I think first you need to learn the stitches - get some inexpensive yarn that's labelled a '4' at the store, and a size J hook or 10 needles. Then practice the stitches by following a video along. See which you like better, because a pattern as well as which craft is mostly personal preference.
sue- knitting heretic