As you reach a certain level you start to learn all the little foibles that you have to learn to get the best out of your kit. After 18 months with my 24-70 I feel I know that lens inside and out, I know how far to push it, I know what it can and can't do. I know without even looking through it whether it will work for the scene I'm looking at. I know what it feels like, in wind, rain, heat or cold. I know exactly what focal length it's on simply by feeling the barrel turn in my hand. I have a couple of other Canon lenses and I know what they can do but somehow I have to work a little harder with them than the 24-70!
I am perfectly normal and sane most of the time, just ask my pack of pink giraffes, they'll confirm it! :LOL:
I like my f/1.8 35mm prime lens for my Sony dSLR. It's actually pretty great for getting close up shots of toys -- images look tack sharp. I use it in lieu of an actual macro lens. Also the 35mm lens was cheap -- about 120 bucks compared to 600 for a a sony macro. I realize I could probably spend about 100-200 on ebay to get a Minolta macro since it uses the same alpha ring, but I'm crazy lazy.
Don't get me wrong, I still want a macro and some other lenses, but this gets the job done.
With the primes you cover a wider focal range for less money with as sharp or sharper lenses that are almost all faster. Also if you drop one and break it, you have 3 others still to use while one is at the repair shop. If you drop the 24-70 then you are crippled until it comes home. (i learned this lesson the hard way, when when I first got into photography I invested in a single, expensive, zoom) Carrying all 4 at once is only 200 grams heavier and if you opt to only carry 3/4 at any given time (since you can probably tell ahead of time what you need) you actually end up with a lighter bag. Also since you have a lighter lens on your camera it will be easier to take stable photos and your neck won't be as sore carrying the lens around.
Sorry for late response. I think you make a very convincing case and I had considered getting at least a 35mm and a 50mm to start off with (instead of OR as well as the 24-70 f2.8).
I think for me though, the worry of dropping lenses is almost a non-factor. I've owned a DSLR and several lenses for 7 years now. 1 is a cheap Nikon 18-55mm kit lens, and the other an equally cheap 55-200mm and the third, a 170-500mm Sigma lens. Also got a 50mm prime this year. I'm proud to say that I've never dropped any one of them. Even though the two Nikon's are quite cheap I always take great care of them. So I'm definitely going to be extra careful with a 1000+ pound (GBP) lens. Incidentally, if I were to go with the 24-70mm, it would be the only lens I'd own for quite some time, so I wouldn't be taking it off the body for a while. Buying 4 separate prime lenses actually increases the chance of dropping one.
I'm getting quite serious about landscape photography now and I always shoot on a tripod in order to use ISO 200 as much as I can, so I'm not so interested in optical stabilization for the 24-70 zoom range.
But I'm not shooting your post down. I definitely did consider more lenses over just the one. I'm not completely decided even now, but currently the zoom is my favorable choice.