Wide angle and 5D

I'm planning to purchase a Canon EOS 5D within the next couple of weeks. I've been shooting with a 400D/XTi for about 10 months now and my preferred focal lengths for landscape has been anything between 12 and 20mm (using the Tokina 12-24 DX),

Now that I'm ready to make the leap to FF, I'm interested in hearing which wide angle lenses (preferably zooms) you guys can recommend?

I've been looking at the 16-35L mkII and I although I have ready some very positive reviews regarding that lens, I think it's just out of my league (price-wise) for now.

Then, I'm looking at the 17-40L. I'm rather curious on any user experience with the combo 5D/17-40. Particulary at 17-20 mm. How good/bad does it perform?

Any tips, suggestions, info would be useful. Many thanks for looking.

The 5D 17-40mm makes a great combo. Owned the 17-40mm and upgraded to the 16-35mm Mk 1 but I don't think it's worth the extra premium.

I like the 17-40 a lot (I've never shot a 16-35 for comparison, but reviewers don't seem overwhelmed by the improvements in the mkII). The main complaint people seem to have with the 17-40 is curvature of straight horizons, but that can be fixed quickly and easily in Photoshop. No lens is perfect. With many nature images not containing straight lines, of course, distortion isn't apparent.

Thanks all. I'm getting a good deal on a 5D with the 17-40L. All new. I'm thinking that's what I'll go for. For now. The distortion I can live with.

I use this combo underwater and find it excellent. The curvature at the corners only bothers me when using it on very close focus.
I have read several times of users being quite dissatisfied with this lens and suggestions that quality varies between units due to poor quality control at manufacture. I don't know if this is true but all I can say is I got a good one. Maybe try before you buy or get it on sale or return.

Let me add a couple things here. The main problem with the 17-40 AND the 16-35 is not curvature of the lens - that's typical of any non-TS 35mm wide angle, but rather edge and corner softness on a FF sensor. In my experience, both the 17-40 and 16-35 do a poor job of this. Canon addressed this issue with the new 16-35 mkII and I now own this lens. It is a huge improvement IMO. Many others agree.

Thank you for your input Marc. I purchased the 5D with the 17-40L today and I think it performs reasonably well, although as you say, it IS kind of soft at the edges.I also notice vignetting in the upper left of the frame (not so much in the other corners). Still, this combination I find is really enjoyable to use and certainly a huge step up from the 400D. The 5D is certainly a fine piece of kit.

I might need to add some more memory to my PC though... It's a pain working with those big RAW files in Photoshop with only 1 gig memory.

I have a really excellent copy of the 17-40 so it isnt always the case.The bowed horizons are literally none existant on mine, very subtle if anything. Others have commented what a good copy of it I have, but it took two returns to the retailer to get it. It operates best and sharpest at f11 and at this F stop it produces the best edge sharpness overall.

David, my copy seems pretty good as well. I haven't noticed much curvature when shooting in landscape format, however, in portrait format I've noticed slight bending. And f/11 is definately sharp. Tack sharp I would say. It isn't too bad at f/14 or even f/16 either.