db2??????? vs. SGMLTools2 vs. what else?

[Gregory Leblanc]

I've been playing around with DocBook and writing some basic documents in
it, and I hear a lot about db2something, which I'm assuming referrs to the
Cygnus tools.  I've also heard of some people using SGMLTools v2, but there
seem to be far fewer people using these.  What else is there for free or
non-free tools, and which ones are giving the best results for HTML and (at
least as importantly), plain text?  Thanks,
	Greg