It's not using the sound card so all digital means one notebook should be the same as the next.
I have this 2009 Sony with HDMI to a TV and such and it's great. http://www.amazon.com/gp/product/B002PHM0L8 and it's running great. Yes we swapped out the HDD for SSD for a last hurrah upgrade.
So anything better would be fine.
I would like to purchase a notebook computer to attach to my AV receiver. The plan is to convert all my music CDs to mp3's and use iTunes to create playlists from the individual albums. I can plug the HDMI output from the notebook into an empty (game) slot on the receiver and have verified that it works. My question is whether there are any notebooks best suited for this. Do all of them play back mp3's equally well? Notice that I don't care about the notebook's internal speaker, just the quality of its conversion of mp3s for signal to be sent to the HDMI cable. Any advice is much appreciated.