There appear to be a lot of reasons for customising the default archiving preferences for Movable Type. I believe my changes have resulted in a more elegant, friendly and future proof system for this site.
On most points I have adopted Mark's approach (Cruft-free URLs in Movable Type), with some differences.
Following the discussion in the comments/trackbacks on the above page was very informative. It's good to know that when I get around to any .shtml or .php fanciness I'll be able to stick to the .html extension. Besides I believe the .html does communicate something useful. So for now I'm not going to concern myself with .htacess gear that I know nothing about.
To compensate for those five characters of "cruft" at the end of all my links I have removed eight others: archives. I feel this is redundant information as the whole site is an archive. This is simply done by changing the values for Local Archive Path and Local Archive URL to match those of the Local Site Path and Site URL in the weblog config.
I also added dirify to the keywords tag in the individual archive path as I expect to often use more than just the one word – possibly cut and paste from the entry:
<$MTArchiveDate format="%Y/%m/%d"$>/<MTIfEmpty var="EntryKeywords"><$MTEntryTitle dirify="1"$></MTIfEmpty><MTIfNotEmpty var="EntryKeywords"><$MTEntryKeywords dirify="1"$></MTIfNotEmpty>.html
Lastly I switched on daliy archiving although, with my current rate of posting, I doubt I'll ever have the need to link to this file directly.