Bad news: the new MacBook Pros still lack HDMI, a very convenient and increasingly ubiquitous way for any laptop to output its audio and video on to an HDTV or receiver.
Good news: it's slightly easier to connect your MacBook Pro to a TV than it was before.
MacBook Pros now support an audio signal over the Mini DisplayPort jack. Believe it or not, the old MacBooks could only output video through that port, and audio had to be output via a separate audio cable connected to the audio-out jack. We can say from experience that connecting previous MacBooks to TVs is usually a slightly laborious affair, involving the purchase of a Mini DisplayPort-to-HDMI converter and all that extra cable tangle.
The new MacBook Pros still require a Mini DisplayPort-to-HDMI converting dongle, but with audio and video being carried over the connection, at least the whole process is smoother--and doesn't require you hunting for your TV's audio-in.
We used the Griffin Connect video display converter, which also includes another adapter to turn the HDMI port into DVI-out. It costs $39.99. Griffin was actually interested to hear how our experiment worked--it even mentions on its Web site that MacBooks don't output audio via Mini DisplayPort. Well, that Web site copy now needs updating.
We connected the Core i7 15-inch MacBook Pro directly to our CNET Lab Samsung LCD HDTV; nothing fancy. It wasn't effortless: we had to activate display mirroring in system preferences, but once we did we still didn't have any audio. We had to make sure to also hit the audio settings and select the Samsung HDTV source for output. Once we did, we couldn't control volume through the MacBook Pro anymore, but the TV remote control raised and lowered volume perfectly fine.
Streaming Hulu videos had audio playback just like you would expect of any HDMI-out laptop.
UPDATE: we hooked the MacBook Pro up to a Denon receiver, under the watchful eye of home theater reviewer Matthew Moskovciak, and played Sin City on DVD. The initial audio stream was in PCM, and sounded good with a few initial drop-outs on the receiver. We then switched audio outputs in the DVD players settings, using what Apple listed as "internal HDMI out," and got Dolby Digital 5.1 audio that sounded as good as HDMI, again with a few odd initial audio hiccups.
We'll confirm once we have a new 13-inch MacBook Pro that it works on that model as well.