I've come to learn quite a bit about different yarns in the last year & have only begun to scratch the surface of what there is to learn about these magnificent fibers! There are two that stick out among the rest that were definate learning experiences for me.
The first one is the LionsBrand Homespun, very beautiful yarn with tons of colors that caught my eye. My inexperience in knitting came through when I cast onto a scarf during a roadtrip. It was very hard to work with, didn't show much stitch definition and the yarn seemed to break quite a bit. I'm a tight knitter & still learning so that project was frogged before we got out of the car. I donated all the yarn I bought (an embarrasing amount) to various people who enjoyed it more than I did.
On the opposite end of the spectrum is my first knitpicks purchase, 4 balls of Comfy worsted yarn in a deep purple. This yarn is fabulous!!! It is luxuriously soft, easy to work with, shows excellent stitch definition & it's machine washable! What more could you ask for? I made a scarflet for a friend of mine & neither of us could stop rubbing the scarflet on our faces because it was so soft. I think this may be my go to yarn when I'm not sure what the heck I'm doing! I know that the money spent on comfy worsted will be well spent, I can always use the yarn for a scarf, hat, gloves, pretty much anything! It's fantastic yarn :)