Advice please on 70-200mm f2.8

Hi all, would appreciate any advice I can get on choosing my next lens. I don't know if I should go for the IS version or not. I mainly take photos in the daytime so I was wondering if I need the IS.
On a clear bright day, I'm getting shutter speeds of around 1/1000th on f4 with my 24-105. I would assume that I can achieve even higher shutter speeds on the f2.8 lens.
With such high shutter speeds, would I need IS?
I've had a chance to test a colleague's rig. He has the 5D and 70-200 f2.8 IS and I was taking some test pics indoors, gotta say that it was very heavy with the battery grip.
Optically, I have read that they are similar in sharpness.
If I opt for the non IS version, I'll even be able to pick up the 17-40 with the cost difference.

Go for th 14-40 + 70-200F2.8 you wont regret it

Thanks for the advice weka.
Anyone else with any advice?

I've been happy with the non-IS 2.8, it's given me great hand-held shots. So my advice would be to go for both lenses.