questions about 17-85 IS

I presently have the 18-55 kit lens. I most likely will purchase a
70-200f4 before a new walk a round lens. I also have the 501.8.
I am looking at the Tamron 28-70 2.8 as well as the canon 17-85.
THE Tamron has a 2.8 lens which will be much more useful
to me than IS. I don't think I will be photographing any dead bodies with
no movement in the future. With the D20's wonderful ISO I
feel I will get a lot more from my images with a 2.8 lens.
(at amuch cheaper price)
I would like to get some feedback from the outstanding and knowledgeable
people on the forum. I think IS on a long lens is fantastic.