Lots of past discussion on this topic. If you have simple needs for xml,
xsl and schema's xml spy has been great for me, the ability to pick the
parser to use (not just the MS default) and the data base components are
useful as well.
Lots of people have given praise to XMetaL. I haven't used it much. I
think its best selling point is its configuration flexibility to suit your
needs and ability to connect to other programs, like i said though, I really
haven't used it much.
I find myself using the good old fashioned notepad and other simple text
editors alot of the time. ah technology.