I must admit that I was going to echo Johan's comments really. If you're wanting to put together a Normandy or earlier impression, then you should order the M41 Field Jacket and Wool Trousers combination.
Also, a word of advice on the M1 Helmet - if you can afford it, I'd certainly recommend that you purchase one of Josh Murray's excellent reproductions. I had a look on At The Front's website and it seems that their 'Economy M1 Helmet' (a picture of which you linked to in your post) actually comprises a swivel bail, back seam shell, and a US Vietnam of Belgian plastic liner. As you might be aware the purist re-enactor would ideally wear a fixed bail shell (or at least a front seam) since this would typically then allow you to portray a number of campaigns. Also, it's preferable to have a correct US-made fibre liner for the helmet, in case you wish to display in the internals.
Of course, as Johan has already indicated it largely depends upon which campaign you wish to portray in your re-enactment.