I knit a lot for the NICU (for non-US readers, that is the Neonatal Intensive Care Unit) at a local hospital, making hats for full-term babies who need special care. The hat the nurses love is this one. I have made at least 15 of these, some in solid colors and others in self-striping yarns. All look great.
You can see many pictures on the Ravelry page, here. Oddly, I don't seem to have pictures of any of mine. I just cast one on; I'll be sure to document it when it's done.
Because it is knit entirely in k2 p2 rib, it stretches or pulls up to fit almost everybody. This is a great feature when you're knitting for an unknown child. The drawback is that it takes a little longer than the quick stockinette caps -- but it is so perfect for this Baby Shower campaign.
I have always used DK weight yarn with this pattern; I think it would also work for worsted that is no thicker than Cascade 220, because the 2 x 2 rib pulls up quite a bit. (For a thicker worsted, knock the stitch count back and adjust the number of rows.) The first set of instructions is to knit flat and seam up; scroll down for the instructions to knit it in the round (always my preference).
Edited to add: make only the largest size, for full-term babies.