The best CCG I've seen is Dominions [1], because it eliminates the more annoying and expensive aspects of the game involving accumulating and managing large, valuable collections of cards. But I've always been more interested in the strategy aspect of games much more than the collectability aspect.

But from a business standpoint, the latter tendency is more desirable to cultivate in players because it's more profitable. When I actively played both, I spent at least an order of magnitude more annually on Magic cards than on Dominion and its expansions.

[1] http://en.wikipedia.org/wiki/Dominion_(card_game)