I have not made it a secret (to you or Canon) that I want a Canon EF 24-70mm f/2.8 IS L USM Lens. With today's announcement of the Canon EF 24-70mm f/2.8 L II USM Lens, my hopes for such a lens in the near future are certainly diminshed.
If you want IS and don't need the f/2.8 aperture to stop action in low light and to maximize background blur within this focal length range, consider getting the Canon EF 24-105mm f/4L IS USM Lens.
Interesting that the Tamron 24-70mm f/2.8 Di VC USD Lens was announced only one day prior. The performance of this lens, of course, remains to be determined.
A big question is: Will the 24-70 L II be worth the $930.00 ($1,030 after instant rebate) price premium over the 24-70 I ($2,299.00 vs. $1,369.00/$1,269.00)? Canon has been turning out some excellent zoom L lenses recently and my hopes are high that this will be another one of them. My prediction is that the II will be worth the price premium - just as the Canon EF 70-200mm f/2.8 L IS II USM Lens was worth its premium price over the Canon EF 70-200mm f/2.8 L IS USM Lens.
It is normal for a new lens model to be priced significantly higher than the previous model. But when the price disparity is this high, the used price of the old model can actually go up instead of down. I've heard from several of you hoping that a copy of the old model might be had at a much reduced price. That the Canon EF 24-70mm f/2.8 L USM Lens price (both new and used) is not going to drop is my (wild) guess.
I have submitted a request to Canon USA PR to receive a call from a Canon technical expert (such as Chuck Westfall) to answer some questions I have (the protocol that Canon USA now requires media outlets to follow), but that call has not yet be returned. I will be sure to update you with what I learn.
The new Canon EF 24mm f/2.8 IS USM Lens and Canon EF 28mm f/2.8 IS USM Lens look interesting. At their relatively high price point, I'm not sure why Canon did not choose to make them "L". These small and light lenses could be very useful. Their performance will of course determine how useful they will actually be.