My experiences so far (most times I get alternative 1):
1.)

Complimentary mini bar
2.)

Big bottle of water (1 lit.) and a fruit basket
3.)

Nothing
I just checked my next stay on spg.com: upgrade to Executive Room, Complimentary Minibar

.
I stay mainly at one of the four Sheratons in Frankfurt and Offenbach.
[This message has been edited by LH738 (edited 06-09-2002).]