PC gaming is set to grow in 2010, according to NPD's Michael Klotz. Klotz hosted a panel here at GDC Online 2010 this afternoon, and said that expected growth can be attributed to two things: StarCraft 2 and World of Warcraft: Cataclysm. PC revenue has reached $303 million as of August this year, and Klotz expects the WoW expansion to put the total over the top of last year's $538 million.

Klotz also talked about the ongoing transition of customers simply buying physical copies of games to buying both physical discs and digital downloads. In terms of revenue, physical sales still outweigh the digital side, but digital purchases (including both full game purchases and DLC) have overtaken bought discs in terms of numbers. That means, said Klotz, that physical purchases are still selling at full price, while customers are paying much less for digital games, either because of sales or because they're buying casual or just cheaper titles online. Klotz credited Rock Band for pioneering the digital move -- lots of players weren't sure about digital purchases until they saw how seamlessly the Rock Band Marketplace worked, and then they were OK with downloading games and game content.

Finally, Klotz shared an interesting stat: Physical point cards (like those for Microsoft points on Xbox Live) have overtaken gamepads as the largest accessory category for game retail in just the past six months. As long as he could remember, Klotz said, game controllers have always been the best selling game accessory, with power cables next on the list. But cards for DLC are now on top of the charts after a 37 percent increase in the past year, showing just how important it is for game retailers to try and get a piece of that pie.

This article was originally published on Joystiq.