I still don't really get the 24-70 recommendation over the 24-105. The f/2.8 isn't fast enough for shooting indoors and you loose IS and the extra focal lens all while paying more for the lens. For me, it makes more sense to get the 24-105 and a "inexpensive" prime such as the 50 1.4 for low light. That or just get 3 primes to cover the range if you are going to spend 1200 on the 24-70.
The replacement has been anticipated for 1 or 2 years if not more now - you'll be kept waiting for a long time.
And about the 24-70 - not fast enough? It's fast enough - especially on the 5D MK II where ISO 3200 is very usable.
Indoors f2.8 is way more valuable than IS for example. Different people value different aspects - I had to chose between the 24-70 and 24-105 for my MK II and got the 24-70 as the 24-105 has no benefit to me.
I've lived without IS so far - hence I do not need it (on a standard zoom) and I can't do f2.8 on a f4.0 lens - while I can simulate the 105mm by croping.
Now you might say you want to shoot buildings at night - then the 24-105 is better for you.
In the end it's a choice of preference - would I give away my 24-70 - no. Would you give away your 24-105 - I'm sure not.
A lot of prime lovers would argue, you really only use the extreme ends of the focal length on a Zoom... so why not get primes and gain the benefit of Low Light shooting and Sharper Pictures.
On the other hand a good L zoom with High End Build Quality, and better AF Motor can be had for anywhere from $1000-$1,300 new. A $1,300 budget of Primes to cover a variety of focal lengths like a Zoom, will only afford you (3) Mid-Grade Lenses... so you lose the better AF Motor and Build Quality.
It's not an easy decision
If prime lovers argue you only use the extreme ends of a zoom then he/she has not used a zoom properly
There is actually and inclination to use the extreme ends - but then you generally are in a situation where you'd love to have a lens to swap to continue in that area.
The advantage of a zoom is that I can look at a scene at 24mm and at say 35mm and 50mm - then decide what I like best, or take several shots - alternatively, it might be that zooming to 56,5mm (the camera does measure ,xmm in the Exif unless I am wrong) exactly crops out some annoying aspect and improves the image.
So in a lot of scenes you'll be zooming in and out with a standard zoom to pick your favourite option.