Haha. Right. I came here immediately because I heard about the Tamron. And what do I see?... Canon picture. Only thing... no IS. Lame! I will seriously look to the Tamron. Probably save 800 bucks. I loved my 17-50 on my 40D.
Surely a coincidence that Tamron have announced theirs today (with their image stabilisation)
"Tamron develops full-size, high-speed standard zoom with built-in image stabilization – SP 24-70mm F/2.8 Di VC USD (Model A007)" Tamron press release (source: NR)