Cite a conference contribution as conference paper of book chapter
Converting/extending a comment to an answer:


I keep a list of talks/posters on my website. I do this to include links to slides, photos and video recordings. When I was applying for grad school I had them in my CV, too. I have the impression that it might have helped. However, once you have a lot of talks it becomes too much info. On some senior researchers' CVs I've seen very compact talk lists: they include their invited or conference talks as acronyms/university names and lists of years. For example, if they regularly present at STOC they might write "STOC 2003,2004,2007". I think this is mostly to show that they are involved with the community and go places regularly.
As Dave mentioned, it is usually standard to cite the paper as a conference. I think the exception is when conferences publish their proceedings, or selected papers, as a special issue of a journal. The only time this happened to me, I had to go through an extra layer of review (first conference, then the journal) for one paper, so I think is appropriate to cite those as journal papers.
A lot of time papers are first published in conferences, and then a year (or more!) later a longer version appears in a journal. The convention is to cite this as a journal paper with a note after: "preliminary version appeared in Conference X 2008".