Auto-update should also be seamless; it should not open a webbrowser asking you to download a file, but instead it should update itself.
I
highly disagree with this one. A user should always have an option to download and install updates themselves. I would suggest a box that would pop up, looking something like this:
New version X found! Install automatically, download from site and install yourself, or continue using old version?
Install automatically [_]
Open site for manual install [_]
Continue using old version [_]
Accept (_), Ignore and do not ask me again (_)
I (and many other "tin-foil-hatters") do not like nor will use software that will automatically update without our consent, and fully-automatic updating does not look good security-wise.