Apple’s new MacBook Pro with Retina display was the big news of the World Wide Developer Conference keynote today, but games also occupied a leading role. Some of the featured items included Game Center coming to OS X, AirPlay mirroring demonstrated for Macintosh, and Diablo III getting updated for Retina Display resolution.

The new MacBook Pro’s Retina display features 2880 x 1800 resolution, and Diablo III is being updated to take advantage of it. “You are going to see a gaming experience unlike any you’ve seen before,” said Apple’s Phil Schiller as he showed screens from the game. Game developers may be paying more heed to the Macintosh, as there are now 66 million Macs in operation, triple the number of 5 years ago. That’s nowhere close to the total number of iOS devices, which Apple announced is now at 365 million, but it’s still a respectable market.

Apple has also refreshed the MacBook Air and MacBook Pro lineups with the latest Intel Ivy Bridge processors and Nvidia graphics, along with support for USB 3.0 and 720p FaceTime cameras. Prices start at $999 for the 11 inch MacBook Air, and at $1199 for the 13 inch MacBook Air. The MacBook Pro 13 inch starts at $1499, while the 15-inch model starts at $1799. All are available immediately.

The new iOS 6 is being released today in beta, with the full release scheduled for the fall. Over 200 improvements are included, including a makeover for Siri, better Facebook integration, notification improvements, and a new Apple-built Maps app. OS X Mountain Lion will be available in July for only $19.99, and will also add over 200 new features to the operating system. Not surprisingly, much of this release is focused on better iOS integration, and bringing many popular iOS features to the Macintosh desktop, building in iCloud, Dictation, Messages, and a new Notification Center.

Apple’s bringing their iOS Game Center to OS X and the Macintosh. Game Center is used by 67 of the top 100 games in the App Store, and now has 130 million accounts. Those gamers are posting 5 billion scores per week. Game Center will soon be featuring challenges, which will be similar to Achievements in Xbox Live. Multiplayer gaming is now supported Mac-to-Mac and cross-device as well.

Even Siri is getting into playing games, as she can now launch applications on voice command. The example given: “Play Temple Run.”