OK, I'm sure somebody (Howard Stringer?) has 400 Blu-ray discs, but fortunately for you, the thing plays DVDs and even "CDs," which I'm told are how they stored music in caveman times. The thing is surprisingly affordable for what it is, $800 to start with means that come Christmas, it'll probably be selling somewhere for much less.
AV-wise, it's got what you'd expect from a high-end stand-alone Blu-ray player, including 7.1 channel Dolby TrueHD and Dolby Digital Plus, DTS-HD High Resolution Audio and DTS-HD Master Audio decoding onboard, plus the ability to bitstream audio to a receiver through the HDMI port.
There's a step-up model, BDP-CX7000ES, that's not so reasonably priced—$1900 to be exact, and it comes with only a few extras, like an RS-232 port for home control, and ability to output Deep Color (12-bit). It's one of those things custom installers will sell to people who have four houses and 16 cars, so most of you shouldn't worry about it.
The Ethernet port on both units connects to Gracenote via the internet, to identify all your movies and pull down graphics. What's not cool is that neither that Ethernet port or the USB port are available for incoming video streams from your own home network. Come on, Sony—get with the program!
Price being reasonable (at least for BDP-CX960), the biggest question is this: Is there value in a megachanger? I myself ripped all of the DVDs I own, so that they fit neatly on a little hard drive, and are ready when I want them. Ditto for music. On the flipside, I don't plan to rip any Blu-ray discs in the near future, even though it's possible. But I also don't plan to own a giant collection of them, at least not until they're selling used for under $10 a pop.
Along with the$800 MegaChanger, Sony is announcing BDP-S1000ES, a $700 Blu-ray player with Wi-Fi. It's too expensive for what it does, and redundant (there's another Sony Wi-Fi model, the BDP-S560 on the way for $350), but at least it's DLNA compatible for home networking, unlike the changers. Still waiting for built-in video-on-demand options like you find on LG and Samsung players, not to mention Sony's own Bravia Internet Video Link, though.
Final thought: In the press release Sony says its Blu-ray player line has 13 devices. In my mind, accounting for both MegaChangers and the upcoming Wi-Fi models, that's still 11 too many.