There should be a mean for the message view mode, that allows to override
message's charset (if any - broken software may not set it at all, or sets
incorrectly) manually. All browser, including IE, Mozilla, Netscape, Konqueror,
and all mature Mail User Agents allow this. Without this Evolution is unusable
for non-english speaking users.
 Evolution already has a widget to select charset from the list (it's in
 Options->Other preferences menu) - so it wouldn't be hard to add such
 widget.