Bev's Country Cottage has a ton of great crochet (and knitting, and sewing,) patterns, but this little sweater one of my favorites. I made several for V before she was born, and it's now one of my go-to patterns for anyone that is expecting. It works up easily in a couple of hours, and there's no complicated assembly at the end. There are instructions elsewhere on the site to add long sleeves, but in our neck of the woods, this version is appropriate for most of the year.
I should mention that it looks much cuter on a teeny newborn baby. :)
I made this one for an acquaintance who is expecting a baby girl any day.