Ken MacLeod is worried about data in RSS feeds being lost with time. The obvious answer is to have an XML feed for each item, with RSS modules like RVW in there too. I think that's what Eric Lunt is suggesting as well, and it's something I was hoping would catch on once Atom is finalised.
Blosxom already does this (applying the RSS template to individual entries is as easy as changing the extension on the URL to .rss), and it's fairly simple to add a new individual archive template in Movable Type to do the same thing. For example, here's the RSS version of this entry.