This could work both ways, first is a way to create backups of the current collection and also will be able to manage collections from other people (we have different collections but pull them on when we create decks) and thus know who owns what

Report for the owned cards with their prices and total price of the collection

It appears that you manually have to note the used quantity of cards in your collection. When you pull a card into a deck, it would be nice to show that it is used. I realize that some people create a variety of phantom decks. But used is a separate column and the card would still show in the collection.

While perhaps difficult to implement, having offline deck testing capabilitiy - perhaps by allowing the user to play a deck idea against a computer opponent using a pre-built (with possible options for tournament-winning decks, particular color/theme decks, etc.) - before actually trying to play the deck live would be a phenomenal feature in my opinion.

You already have the option which cards are missing from a predefined deck, but what we would really love it the possibility to see which decks can be built with the cards we currently have. So that is auto-checks which decks are only missing very few cards.
I know this might be processor intensive, but my... that would be one of the best features you have ever done.
Keep it up.

I would like to see an app on the Android market to allow you to view your collection from an Android device.

Have button which allows to switch between front and back of the Duel Face cards.

Build a web site with the same functionality like MTG Studio which is
- cross-browser
- cross-platform
- allows you to maintenain your collection/decks from anywhere
- zero installation
- no Flash, Silverlight, etc.
- subscription bases. Something like $1 per month, $10 per year..

Add the ability to set the buy at or sell at column to a store price or % of the store price.

Work on Options dialog allowing you to select the way the default price is calculated.
- be able to pick favorite store
- be able to pick AVERAGE, MIN, MAX price
- be able to pick a weighted price depending on store availability
- be able to add a Modifier index to the prices. For example Store Price - 20%.

Thumbs View. Ability to display the cards with images instead as grid rows as in MTG Online.

Enable prices to update to include the quantity field as well as correct prices for foil cards.

So example: Say you have 26 Tear Drop Kami's in your collection. The price field should say 5.98 instead of 0.23. 26x0.23, in other words.

Also, prices for foil cards are listed to be the same as non-foil. This is incorrect. All foil cards, common-rare, have different prices then their non-foil counterparts.

thanks.

Add "Batch Addition..." command which allows you to add a whole set, or all filtered cards, or all selected cards from either card pool or deck to the collection. The dialog will default the possible editable column values and allow changing the default values.

To track my Frnech/English/Italian/other cards

make a companion ipod ap to export collection...so no matter where you go you have your collection with you...this would make your offerings complete

Add column price in the deck grid which shows the average price of the card (similar to this in the collection). The total to be calculated as SUM((Qty+SB)*Price)

Is there a way to turn off some of the warnings? When I am building my collection and I double click to add another card of the same type, I get that warning asking me am I sure? Is there a way to disable this and just increment by one?

Allow to select from Options whether Original card rules or the latest Oracle rules will be displayed in the grid.
The same should go for the Original and Oracle card types.

Decked Builder is an IOS/Android App that also has a deck and collections feature. It would be great to be able to import/export decked-builder collections and decks to be able to edit decks and collections on the go.