1. The Concise Oxford English Dictionary
Short comment: The book has relatively high translation compared to the counterpart 新牛津英汉双解大词典, and also of course authoritative and comprehensive enough.
2. The English-Chinese...
I found New Century English-Chinese Dictionary is lack of "Culture Note" and "Usage Note" sections, which appear in paper edition.
These sections are very useful features in the dictionary. Hope they are included in the future.