Another Baby Surprise
At the risk of repeating what everyone else has said, this really is one of the most fun patterns to knit, ever. I've always loved the practically seamless baby sweater from Knitters Almanac and have made it a few times, and for some reason resisted knitting this pattern. It's super fast-- I got it done in under a week of very limited knittting.
Yarn is Sierra Aran from elann.com, which is a great yarn, so many beautiful colors and it shows texture wonderfully. Also, unlike another of elann's yarns, it wears great, no pilling whatsoever.
However, I wouldn't recommend it for a baby sweater, because it's not machine washable. I thought, hey, I'm a knitter, I know how to care for wool, my baby can have one hand washable, etc... and right away I regretted it. He's already felting the placket with drool and teething, and if there's any mashed banana anywhere, it will find its way deep into this sweater immediately.
If you are knitting for a new baby and mom, please please ignore EZ advice on this matter (however charming) and use washable wool. The new mom will thank you.
Edited to add: If you're making longies to use over cloth diapers, of course still use regular wool. I don't think washable wool lanolizes as well.