Hasbro (owners of Wizards of the Coast) just released their sales report for Q3 of 2008 and according to it Magic the Gathering and Duel Masters are both up in sales.

To quote from the transcript of the report: "Traditional board games were up 7%, with a number of games performing well in the quarter, including Scrabble, Trivial Pursuit, Twister, and Guess Who. In our Wizards of the Coast trading card business, both Magic: The Gathering and Duel Masters were up significantly."

Source: SeekingAlpha.com