My first knitted hat (I started with crochet) was 'It's a Man Thing - by Justyna Lorkowska'. It is generously a free download via Ravelry.
I started first thing in the morning, using an 8ply/DK yarn (rather than the Aran called for) from SkeiNZ. I find that this yarn has a slightly larger gauge than a 'standard' 8ply. It is plied a little more loosely than a 'normal' DK (ie. Moda Vera Pure Wool) and its a bit more 'fluffy'. Using the same size needles called for, I got the stitch gauge, but not the row gauge.
Because of this, I added an extra 1/2 inch to the ribbing, then just continued as normal. It fit perfectly, and he wears it everyday (that it's cold anyway).
It took me 8 hours, using magic loop, and I used 2 yards shy of a 50gm ball.