Is HTML E-mail Still Evil?

Charlie Campbell asks: "My boss is pretty adamant about getting HTML newsletters to our clients; and, I'm pretty adamant about finding an alternative. I can understand the benefits in HTML mail from a designer's (mine) and marketing standpoint (that of my boss); yet, based on foreseeable issues with recipient software, mail filters, dial-up connections, etc. I feel that the risks outweigh the benefits. We've all heard this a million times... but is it now an outdated concern? Should I trust our client-base to be fully equipped for such a mailer? Should I worry about improper delivery marring our professional image? Is there anyone documenting the issue from a current-day perspective?"