You need to index each item in your collection. The issue with your code seems to be the use of foreach. You really want to use for instead and pass in the index with the EditorFor call.
for (int i = 0; i < Model.Items.Count; i++) {
@Html.EditorFor(m => m.Items[i])
}
This only works for ordered lists that will never change their order. If you want to reorder items I suggest your read Phil Haack's great post on sending lists to the server.
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx