Ikea is better for measuring cups than Coop. For dry, such as flour and sugar, measure by weight, not liters. And yes, use a scale. I also regularly refer to an old Joy of Cooking that has 5 pages of measures and equivalents. And this is a quick and easy reference: http://www.joyofbaking.com/USMetricVolumeEquiv.html.
That said, I keep my old cup/tsp. etc. measures and routinely use them for US recipes. Here's one I just posted on our food pages, for pumpkin bread :-), using US measures: http://genevalunch.com/the-rambling-...o-the-kitchen/