If it's something personal, I use http://archive.is with their bookmarklet in Chrome (free; unlimited archiving). It immediately renders the page, saves a copy with a unique url, and gives me a .zip link to download the archive.
If it's something I want to submit to the Internet Archive, I use wget with WARC extensions (http://www.archiveteam.org/index.php?title=Wget_with_WARC_ou...), submit the archive to the IA and notify them it needs to be merged in, and keep the .tar.gz archive.
Eventually I'll webapp/one-click the whole thing, with an archive to S3 and/or Glacier.
If it's something I want to submit to the Internet Archive, I use wget with WARC extensions (http://www.archiveteam.org/index.php?title=Wget_with_WARC_ou...), submit the archive to the IA and notify them it needs to be merged in, and keep the .tar.gz archive.
Eventually I'll webapp/one-click the whole thing, with an archive to S3 and/or Glacier.
Disclaimer: archiveteam participant