So much for that big Apple event at the end of March. The company decided to launch a bunch of new hardware today with no fanfare beyond two press releases.

As anticipated, Apple refreshed its Mac mini and iMac lines, but it threw in a few bonus updates as well with new Mac Pros, Time Capsules and AirPort Extremes.

The iMac now comes in four versions: An entry-level 20-inch version and three 24-inch models. All of the 24-inch models now come with 4 gigabytes of RAM standard. There is a 24-inch version that is $1,499 for the first time, while the 20-inch version runs $1,199.

The new Mac mini features a new backside with a bunch of USB ports and a Mini DisplayPort. Yes, those early leaked pictures were real despite those who were sure they were fake. Most significantly, the machines received new NVIDIA GeForce 9400M graphics, as expected. There are two models, with the entry level one still starting at $599.

Apple chief operating officer Tim Cook (who has the helm with Steve Jobs on medical leave) claims the new Mac mini is “the world’s most energy efficient desktop computer.” Apple says it draws less than 13 watts of power when idle.

The new Mac Pro comes in two standard versions: One with 4 cores and one with 8 cores. Both feature Intel’s “Nehalem” Xeon processor. Apple says the machines have a completely redesigned interior. It claims that despite shaving $300 off the price of the Mac Pro, it can deliver up to twice the performance of the old version.

The new Time Capsules and AirPort Extremes are the same except they now support setting up networks for guests and simultaneous dual-band Wi-Fi, which Apple describes here:

For maximum range and compatibility, Time Capsule works simultaneously on both the 2.4GHz and 5GHz bands, allowing all the devices on the network to use the most efficient band automatically. And Time Capsule uses the latest 802.11n wireless technology so you can enjoy up to five times the performance and up to twice the range of 802.11g wireless networks.