Recently some work of mine was presented at a prestigious conference by the second author on the forthcoming journal article. On the write-up submitted to the conference I was listed as first author, but was unable to attend for personal reasons. How should I list this achievement on my resume whilst still acknowledging the roles played by each author?
A CS view on this - other fields (even other subfields within CS?) may have different conventions:
It is irrelevant who gave the talk. It may be the first author, it may be one of the other authors, it may be someone else entirely (e.g. if none of the authors could come to the conference for some reason).
During the presentation, it is important for the audience to know who is presenting, which is why in the presentation slides, the name of the person may be highlighted. However, that is not so much to assume much credit for the work, but to give the audience an indication of who they are talking to; how to address the person in the case of questions, and just to associate the right name with the right face. In a well-functioning team of several authors, chances are that the slides were not done by a single person, anyway, so the slides themselves are again a group product of several or all of the authors.
Bear in mind that, while a publication on a conference is generally assumed to mean that one of the authors presented the paper, extraordinary specifics of how the presentations were done are generally not listed anywhere, neither in bibliographies, nor in CVs. Additional people who presented, but were not authors, never appear there, nor do hints about "exotic" presentation methods (given that there is tremendous variation in what a "poster presentation" means, depending on the conference, I can well imagine that for some conferences, a "paper presentation" is not necessarily the traditional stage talk + slides).
Such details might be slightly interesting, but at the same time, it would just be too cumbersome to keep track of all of them, so lastly, the core of your work is the paper/article that gets included in the proceedings, and that is what you refer to.