I don't really like Ken Rockwell. I mention it in passing on my Facebook in moments of passion, but I've never really just... said it in a normal fashion. I'm sure he's a nice enough guy, who is a great father, and is obsessed with his kids, and I admire his desire to catalog an absolute mountain of information, and his (apparent) love of helping beginning photographers. Also, in the past, he used to be the first to get some nice Nikon gear and give really detailed write-ups, but even that seems to be waning as of late now that he claims to hate digital, or that $150 cameras are just as good as $5000 ones, and tells everyone to buy either a Nikon D40 or a Leica. I warn everyone who asks me for advice to be sure to take his opinions with a grain of salt. His tech reviews are fine, but when he starts throwing around opinions, he's doing more damage to beginners than he is helping. This is a guy who contradicts himself more than is humanly possible (e.g. he claimed once that 16mm was the same thing as 14mm after writing an article stressing the magnitude of difference between 14 and 13mm) and thinks that mid-level consumer gear is the greatest thing ever to have happened (While the D7000 is great, it's not better than a D3s, as he suggests).
But while most of his opinions are pretty wishy-washy and change every two seconds, there is one that I agree with completely: The mid-range zoom compromise.
One of the most often-asked pieces of gear advice I get is on Nikon's 24-70mm f/2.8. Afterall, it is the middle of the Nikon Holy Trinity made up of it and the 14-24mm f/2.8 and the 70-200 f/2.8. What could possibly be bad about it? The short answer is "technically, almost nothing." The Nikon 24-70mm is high-end professional glass. It's a $2,000 monster of a lens that is built to be optically fantastic, and tough enough to take a beating. It really is the world's sharpest mid-range zoom, and it will withstand the toughest of conditions with its solid metal construction and weather sealing.
The problem isn't with the lens itself. The problem is with the concept of the mid-range zoom. I've written before about how 50mm (which is considered THE midrange focal length) is a total compromise. Well, a mid-range zoom is a total compromise, and I don't think the compromises are worth it. First off, it's not as flexible as you'd think. A maximum aperture of f/2.8 is fantastic in a telephoto lens. The longer the lens, the shallower the depth of field. 200mm f/2.8 gives GORGEOUS shallow depth of field and massive amounts of compression for very strong, flattering portraits. 70mm f/2.8, not so much. There is a reason the best portrait lenses in the short-telephoto range (e.g 85mm) are f/1.4 and f/1.2... And it just gets worse as you zoom out. 35mm @ f/2.8? While that's a great wide field of view, you aren't going to get any usable depth of field control. At all.
And maybe it all just has to do with what is important to me. But then again, I'm not the only one. Take a look at any hardcore, legendary photojournalist's rig... We're talking war corespondents. The majority of them of them will have a camera on each shoulder, one with a 70-200, and the other with a wide-zoom or 24/35mm lens. No compromises. That's a setup I enjoy as a wedding photographer as well. I like my images very wide, or with a nice telephoto. The midrange is boring. The midrange is a total compromise. Not to mention that while the mid-range zoom gets wide enough, it's going to have distortion that you just won't get from primes. That's just how zoom lenses work. The extreme ends of the zoom range will always have some sort of distortion compromise.
So what do I recommend? I recommend that you get a fast 50mm and a 24 or 35 (or a wide zoom that has one of those. You'll produce more compelling images without sacrifice. It's not a big deal to change lenses, I promise. Stop being lazy and use the right tool for the right job! Sometimes people will recommend a mid-range zoom if it's the only lens you're going to take with you on one body, and while part of me agrees, the other part of me says that you'd be happier with the results of one fast prime (35 or 50mm), and it would push you to find different perspectives, which ultimately makes you a better photographer. What do I do when I leave the house with one lens? Sometimes I'll pick something random to force myself to try something different. Most days it's my 85mm... which isn't an optimal "every day" lens by any stretch of the imagination, but it makes you think. It makes you try new things. As of late (and probably why my Project Eighty-Five has suffered), I've been walking out of the house with my 50mm f/1.2. Either-way, I have never been upset for not having a 24-70.