Here's why: You can't send a 3D signal from your 3D Blu-ray player to your 3D HDTV if you have daisy-chained between them a receiver that doesn't support 3D. If you don't want to upgrade your receiver, your only option is to connect the Blu-ray player straight to the HDTV, and directly via another cable to the receiver. If the player has only one HDMI port, as the BX580 does, you'll have to use an optical connection and sacrifice sound quality.
On the plus side, the BX580 offers two ways to connect to your home network and, through that, the Internet. By way of the built-in ethernet or Wi-Fi connections, you can use LG's connected services; they're small in number but represent a good selection, including Netflix, YouTube, and two different pay-per-view services, CinemaNow and Vudu.
The BX580 can also use your network connection to play and display videos, music, and photos off local computers. Each computer will have to be running DLNA server software, but any Windows XP, Vista, or 7 PC already has that with Windows Media Player. And as with virtually all current Blu-ray players, you can plug a flash drive or external hard drive into the player's USB port and enjoy your media that way. The BX580 supports a wide selection of audio, image, and video formats, and allows you to play slideshows with transitions and your choice of music.
The power and eject buttons sit on the top of the player by the front, making them easy to see and access. Unfortunately, a reflective 3D sticker on the front of the player can be annoying if light is hitting it, and the sticker won't come off without a fight.
When you turn on the BX580, the whimsical home menu shows icons floating in what appears to be the ocean. Clicking the Setup option brings you to a more conventional menu. The menu offers descriptions of its options, but they're not always helpful: The Initialize option, for instance, is explained as 'Initialize BD-Player'. (The manual is more informative, explaining that the option will return the player to its factory settings.)