We used to use Visual Source Safe and there was one neat feature that I can't find in TortoiseHG. You right click on a file and click "Show history". VSS opens a list of versions for that file. Then you select two versions (ie: version 50 and version 47) and click the compare button to launch a visual diff of the two versions.
How can I do that with Mercurial/TortoiseHG? I saw the annotate feature but only compares consecutive versions of a file.