HDMI can carry sound but I don't know if DVI can. Maybe, maybe not. I haven't investigated it.
HDMI carries sound, but DVI does not.http://en.wikipedia.org/wiki/HDMIhttp://en.wikipedia.org/wiki/Digital_Visual_Interface
Nevertheless, typical graphics cards DON'T have sound card functionality integrated... so a sound carrying DVI->HDMI adapter cable would be a waste of money... IF it's even possible to carry sound through DVI.
That is just plain wrong!
ATI Avivo HD technology found in the ATI Radeon HD 2000 Series enables stunning big-screen entertainment with advanced hardware HD video processing (UVD*) and HDMI connectivity that includes built-in 5.1 surround audio.
ATI has had audio chips in ALL of their GPUs since the 2000 series.
Remember both HDMI and DVI use digital signals. It's not like there's a separate wire for video and audio. If the GPU only has a DVI out port physically, but supports HDMI, then it must detect if it's connected to a device with DVI input or HDMI input, and decide if it can also send audio to the device. It's not really about the cable or the ports, but the capabilities of the input device.
With future GPUs (hopefully) coming with native HDMI, I hope there'll be sound card functionality implemented on them as well. At least 2.0 stereo as most TV are capable for at least that. Especially for laptops, I hope HDMI would become defacto standard for external displays instead of that VGA output they have had so far.
It's already been quite some time since the first 2000 series ATI card was released, with builtin audio through HDMI, like I already said. They can do 5.1 on 2000 and 3000 series, 7.1 on 4000 series.
It's just trivial that VGA port gets replaced, since all current display technologies have digital input natively, and the computer has digital output natively, and thus using an analog transport means having to do 2 extra conversions to the signal. Circuitry for doing this costs money. Soon GPU's won't have this circuitry at all any more, because they are not needed. There can still be niche market GPUs that include this circuitry for the minority that need them.
However it shouldn't probably be HDMI which wins, because HDMI license is not free, and so all devices that implement it must pay royalties, which also means devices are more expensive for the consumer.
The better format is the DisplayPort, which is totally free to implement.http://en.wikipedia.org/wiki/DisplayPort
It has all the capabilities of HDMI. There are already GPUs with DisplayPort out. Support for it already was in ATI's 3000 series, and is in 4000 series also, but sadly GPU manufacturers don't enable it on all models, because it needs a physically different port, and you can't just use an adapter like with DVI->HDMI.
There's also monitors that have DisplayPort input, though not so many yet. Mainly this year 30-inchers.
While VGA output does work with 1920x1200 computer monitors, it usually doesn't work with 1920x1080 TVs! The limitation is within TV's end and it can't receive high-res analogue signals. Also, with the need for a cable to transfer audio to TV set, playing HD video on a table TV streaming from laptop computer takes a while extra to set up. HMDI audio connection would not only reduce number of cables but also eliminate effect of noise when transmitting the signal to TV set.
Indeed for the PC -> TV mainstream usage the analog connects will disappear soon, since all of that is already available just the way you wanted.
Alas, nothing of this is available on Nvidia.
Disclaimer: My current card is Nvidia. However I don't need those features myself, as my audio goes from my PC to my standalone stereo amp and from there to my speakers.