I switched to digital before I bought a 17-35 or a 20-35, but I do own a 24 2.8 D. I've never used the 18-35 that you mention, but if it has the same build as the 24-85 3.5-4.5 AFS, I'd skip it. I bought that lens last year and it's about had it. Of course, I put gear through tough conditions, but still. My 24 2.8 D on the other hand has been a camp. It's light, it's sharp, it focuses fast, it's small. It makes my FM3a feel really nice, and I love it on my digital also. It's a great little lens, and was my favorite when I shot film. Now with digital, I use my 12-24 more often, but every once in a while, I shoot for a week with just the 24.