I watched a program on this on Oprah the other day. It was interesting. From memory they recommended you couldn't do without:

1 coloured mac
1 roll neck jumper in a dark colour and 1 in white
1 pair of dark trousers in the cut that suits you
1 tunic
1 pair dark jeans (washed inside out to prevent fading)
1 pair of white jeans
1 casual jacket - problaby white
1 oversized handbag
1 pair of flats (shoes - preferabley leopard skin for some reason!)
1 white blouse
1 black dress

Can't remember the rest! I'm sure we need more than this - but it could be a good start!

I think the capsule wardrobe may change depending on your circumstanceds - for example if you work outside the home you may need different things than if you don't.

I'm interested in what other think.