We have spoken about All You Knit Is Love. It's a great book, full of classic designs. Most are quite suitable for a beginning knitter, too.
And there are Balloon Pants, which I made for a dear friend while she was growing her little girl.
Well, the sweet baby girl is finally ready for her pink pants. Her mom and I were not sure how they were supposed to fit and flatter, but baby girl seems pretty pleased. I could not be happier with the whole thing.
I made mine with one skein of lovely handpainted sock yarn, so any of our new socks yarns would be perfect. For the Balloon Pants, I would stick with a semi-solid sock yarn rather than a highly variegated or striping yarn. The details will get lost otherwise. There are several other designs in the book that would be great in a busier yarn. I think I need to grab a skein of that locally-dyed Bumblebirch sock yarn and cast on for another pair, because these were so much fun to knit!