I have the 8350i and cant read .tif files when attached to an email...
Specifically, I have my office phone and fax forwarded trough my AT&T unified messaging to my Yahoo email account which in turn shows up on my blackberry. The phone messages show up as a .wav file and I can preview them just fine. However, the faxes show up as .tif files and my blackberry calls these files an unsupported media type... I can however read .pdf files...
I do have the 4.6.2 attachment service installed per my options menu...