My daughter is 3 and my son is almost 5... and I honestly haven't noticed any huge differences so far!
True to stereotype, my son has been more rowdy and naughty... but my daughter is also younger, so she may yet become rowdy like her brother. One thing I've noticed though, is that she picks up qualities from her brother. He loves to build with blocks and to do arts & crafts projects, so that's what she loves too. So in that sense, the desire of the younger sibling to copy the older sibling may be evening out any differences so far.
I'm sure there will be more differences over time, as the kids get older and (more) hormones kick in! So far though, I've been surprised at how similar raising a boy and a girl has been.
Do you find parenting boys and girls to be very different?