D2stats is a very nice utility.
I'd highly recommend it for a variety of reasons, ranging from beginner --> advanced.
For example, D2stats can reveal the ilvl of an item, FCR/FHR/etc totals on your character, how many sigs you've consumed, etc.
You might not know what those are, yet, which is fine. You will.
However, the dropfilter feature may be of immediate interest to you.