Le Creuset shallow casserole that is used far more than any other cooking vessel I own.
Love this - all it does is remove the zest from lemons and lime, but it does it brilliantly.
It's amazing how many things that I cook start here.
A cheap Japanese cleaver - costs about £8 in the UK, frighteningly sharp and can joint a chicken, slice cabbage as fine as you like for coleslaw and crack lobster claws!
It's a coffee mill - useless for coffee but brilliant for grinding spices.