What exactly do you pack in your hospital bag?

Make sure you pack your hospital bag by 36 weeks is the advice I was given when I went to a recent Parent Craft class. Ok. Will do. But what exactly do you pack or more importantly how on earth do you manage to get everything you need together? After all no one knows how long you will be in hospital for. Plus the fact if you know me then you'll know I never exactly travel light.

Thankfully I was also provided with a list of suggested items to bring in (see list below) and have so far managed to get quite a bit of these items together. 

However, when it states "clothing for baby" what on earth are you meant to bring then? Ok if it's cold you'd bring something warm to wrap him in and if it's warm you'd bring the opposite but how on earth are you meant to know what size he will be? Or his weight? The last thing I'd want is to be told off my the midwives for dressing him in an outfit that's too small or too big. 

So what do you do? Any mums out there with any advice please feel free to share.