As a collector, I think it would be extremely helpful to be able to specify whether you have multiple cards from different expansions. Especially with foils, other special deck releases, etc.
In case this doesn't make sense, here is an example;
I have about 8 different Pacifism cards; 4 from M10, 2 from 7th, and 2 from 9th. I know that in the card database it shows what editions the card is available in, but as far as my specific inventory, it does not specify how many from each edition I own.
I have all my cards sorted in binders by edition, and it would be really helpful to be able to see how many of a card I still need from each set.
Otherwise, I think this site is awesome, I only wish I could get ahold of more people for trading. Otherwise, I have nothing else to add.
Thanks!

But there is a way to specify the different editions of your 8 Pacifism cards. See sebi's post: http://deckbox.org/forum/viewtopic.php?id=69 . You can edit each card's individual details using the red arrow to the left of the name in your inventory.

As Laura already said, you have to click on the little red arrow, to get a card menu. From there, you can select specific details.

The card listing will then look something like this: http://deckbox.org/sets/703?s=i&o=d&c=icte. The edition symbols at the right of the card name are the actual editions the card is from. The edition symbols in the Rarity / Edition column to the right are actually just the last printed edition for each card.

Yes but beside showing what edition are the cards from, it dosn't help you. I mean in your example, Sebi, Victor has 2 garruk, one from Lorwyn and one from Duel Deck. But which of the two is the foil one? Or are both foils?

Another example is if, let's say i have 4 card from which 2 are from x edition and 2 from y edition. How do you know which is which and how many of them you have in an edition?

You click the editions icons and see in the dialog how many you have from each edition :)

I personally don't care if my garruk is from lorwyn or m10 and i wouldn't want my inventory view to get convoluted and mixed with too much information. i think opening the dialog and seeing the detailed information is enough.

Thanks for edumacating me about the little red arrow!!
That really does help (I think).
And sorry about the delay in response. Didn't mean to just post and run!