Work Around for lack of HTML email on Bionic:
I, and many others, have had a problem with non-gmail email that is formatted with HTML appearing as an attachment. Apparently, the Bionic does not support HTML email. You can't view the attachment unless you save it, leave email, open Quick Office, open browse, open internal storage, open messaging, and then open the saved file. Whew, that's a lot of work!
Fix: Have Gmail fetch your email from other accounts. You need to open gmail from a computer, go to Settings > Accounts and Import, select Check Mail Using POP 3: > Add a POP3 Account You Own. Follow the instructions for your email account. Your email will now show in your gmail account on your phone and computer with the html visible.
Hope that helps! I am posting in Bionic threads as well since this seems to be a Bionic specific problem.
Dave
Edit: I downloaded K-9 and it displays html just fine!!