I've added an RSS2.0 feed today, although it's generated from the default Movable Type template so it's less rich than the RSS1.0 feed, and doesn't include full entries. If you have the ability to use either, use the RSS1.0 feed. The numbering of RSS versions is actually deceptive -- RSS1.0 and RSS2.0 are two completely different things, and in my opinion RSS1.0 is the superior format.
If I find that somebody's put together a Movable Type template for RSS2.0 that produces feeds as rich as Ben Hammersley's RSS1.0 template I'll gladly copy-and-paste it, but unfortunately I don't have time to learn and play around with it myself.
I don't think it's too much of an issue, though, since most of the major aggregators deal with RSS in whatever form you throw at them. Plus I think I have about 2 regular readers who use aggregators. But it's there, in the event that it's needed by anyone.
Nucleus blogs spit out a .91 Feed and 2.0 one. I always wondered if there was anything really differeny from .91 and 1.0
As I understand it (which I probably don't) RSS2.0 is a direct evolution from RSS0.9x (both products of UserLand), while RSS1.0 is totally distinct, RDF-based, heavily extensible and semantics-oriented. I guess some people keep RSS0.9x around for backwards compatibility with old software, but I believe the spec has been superceded by RSS2.0.
I'm with the RSS1.0 guys on this for three reasons:
1. I used RDF myself in a research project a while ago, so I know a little about it and I'm interested in its applications
2. Modularity and extensibility are central to RSS1.0
3. The more I read of Dave Winer's writings, the less inclined I become to follow him.
But it's not something I either feel that strongly about or in which I consider myself well-versed, so take everything in this comment with a large pinch of very coarse salt.