For starters, using Word, you can only mail merge to HTML format if you are
using Word/Outlook 2002 (and in that case you will probably be better off
with Word/Outlook 2002 SP2) or later. Even if you have Word 2002 and the
HTML format option, the full Outlook is the only e-mail client sottware that
lets you send in HTML format.

The other way you can send formatted info. is to send as a Word doc. in an
attachment but
a. the message body is blank
b. obviously it requires people to have Word (or something that can read
your Word document) and to open the attachment.

FWIW, only plain text e-mails "look good" to me, but then I'm probably
old-fashioned :-)