24-70L or 35 f2

On your 7D, the 35/2 should do pretty well, even @f2, the edge distortion you would see from that lens on a FF sensor is largely cut out. You're in the sweet spot. So while the 24-70 (even @f2.8) is sharper than the 35/2 (@2.8), most of the difference is due to the poor edges, and so is a moot point on your 7D. If you were shooting w/ a 5D it'd be a different story.

Only you can say whether the 35mm (eff 56mm) focal length is going to be wide enough for you, and by choosing the prime, you won't even be able to approach WA FOV, Personally, I'd consider a 17-55/2.8 IS or a 17-50/2.8(tamron) instead, given the limitations of that (35mm) focal length. Certainly you won't be loosing much light, and the IS & FTM USM of the 17-55 make up for a considerable amount of limitation in the 35/2's capabilities. Plus, it's easily as sharp as the 35/2.

I have both lenses and do own the 7D. I find that I rarely use my 35 F2 as the 24-70 has very similar IQ and is a lot more versatile. However, I mainly use the 24-70 on my full frame bodies. On my 7D I tend to mainly use my 16-35 f2.8 II as it makes a better standard zoom. So while I find the 24-70 gets used a lot more than the 35 F2 I tend to use both these lenses mainly on full frame. In the case of the 7D I do not find the 24-70 that useful a FL range (effectively 38 - 112mm). If I were in your position and did not plan to buy APS-H or Full frame bodies i would look at the 17-55 F2.8

I use the 24-70 on my 7D where I like the fact that at the 24 end I can get FL body shots without excessive distortion. The zoom range also works well if you want to grab a quick portrait or 3/4 shot.
I also use the 50 F1.4 on my 5D (similar FOV as the 35mm will give you on the 7D) and often find it limiting if the space is tight. I expect you will find the same with the 35mm on your 7D.
IQ wise the 24-70 is a super performer, both on the 7D and the 5D.

I think for me the deciding difference would not be sharpness but other things like flexibility (24-70 wins) against weight (35mm wins).

Also durability. The 24-70 is a very robust beast...the 35 F2 not so much at all. Having said that, I have never had a problem with the 50 F1.4 which has similar build quality to the 35 F2, but I have also used it exclusively in the studio which is quite a sheltered environment.
The 24-70 is well known as a tough lens.

Depends on what you are doing. I find that for shooting video what may seem like only a little extra speed F2 vs F2.8 can make a big difference in terms of video lighting power especially if you are running them on batteries. I use the 28 1.8, 35 F2.0, 50 1.8 and 85 1.2L. However I plan on selling the 85 1.2L for the 85 1.8 because the 85 1.2L is just too big and heavy to carry with me often. However, it speed is not a big issues I would recommend the other lens I use often the Tamron 28-75 F2.8 DI (excellent lens).

J C, I would go back over my images before your 24-70 disappeared and see what focal lengths you used most. That might inform your decision better since you already owned one.

If a gun were held to my head to make a decision, I would go for the versatility of the 24-70L :)

The 24-70L is a no brainier as a better lens but it's massive compared to the little 35mm. Hard to get candids with the 24-70L stuffed on the front I would think.

And of course cost. Depends on what pictures you take I would say. I'd get both, a second hand 24-70L and a new 35mm, super lenses!