Why is my bread so dense and moist?
I was watching a Lorraine Pascale (British baker / chef) episode on TV before. She had a saying which was "when it comes to dough, the wetter the better". Don't get tempted to add more flour if your dough feels wet. She also used a mixer with a dough hook AND allowed the machine to knead it for 5 minutes.

After kneading, gently shape the dough into a rough ball shape and with a floured finger press into the dough. If it's ready, the depression in the dough should spring back so you can't see where you pressed in.