Apple's tablets may have been the marquee attraction, but they weren't the only hardware unveiled Tuesday. Perhaps the most eye-catching update was the new iMac lineup, featuring dramatically thinner versions of Apple's all-in-one desktop.

The iMac still sports the aluminum design that's been in place for more than five years, but the insides have been re-engineered to make the machine lighter and thinner. The new systems are 45 percent skinnier than their predecessors, according to Apple; they're also about 8 pounds lighter.

The new iMac comes in 21.5-inch and 27-inch sizes, with prices starting at $1299 for a 2.7GHz quad-core Core i5-powered version of the smaller one. The other 21.5-inch iMac features a 2.9GHz quad-core Core i5 processor for $1499, while the 27-inch offerings sport a 2.9GHz quad-core Core i5 or 3.2GHz quad-core Core i5 for $1799 and $1999, respectively. The 21.5 inch models will ship in November, the 27-inch the month after that.

Among the build-to-order options for the new iMac is the newly announced Fusion Drive, a hybrid storage device combining flash storage with a regular hard drive. The Fusion Drive features 128GB of flash storage and 1TB or 3TB of hard-drive capacity. Apple hasn't announced pricing or availability for the iMac upgrade.