billybudd-
I sort of hijacked your thread and took it in a different direction. But I didn't forget why you posted. And I do have a couple of comments. Keep in mind that I don't own any Nikon equipment and my thoughts will be more general and not about Nikon lenses.

Regarding the 12-24mm f/4.0 - I was jealous of this lens when Nikon first introduced it. It took Canon a couple of years to come out with a real wide-angle for digital SLRs. That's why I own a fisheye. Anyway, you say you use it for architecture. I'm wondering about distortion. Does it bother you? If not, no big deal. But if you have problems with architectural images, you might consider adding a super-wide prime lens. Canon has a corrected 14mm f/2.8 that I covet. I checked and didn't see anything that looked equivalent for Nikon. But that might be a nice addition to what you have.

The 28-200 D - This lens is sort of like my Canon 28-135mm IS. The Cano was introduced well before digital SLRs became the norm. The 28-135mm IS was considered an excellent all-purpose lens, but it's popularity has declined since people started switching to digital. Besides the focal length issues caused by smaller digital sensors, I've also seen more complaints about image quality. Either Canon quality control has declined, or more likely, the digital SLR sensors are more demanding and show up problems in the lens that weren't as apparent with 35mm film. Regardless, I love it on my EOS 10D. When I combine it with the 15mm, I have a very powerful and flexible setup. And even if the image quality isn't tops, I can get that kit to places where I'd have a really, really hard time getting the 70-200 f/2.8L and another wide zoom. And the image quality really is very, very good. Good enough to sell photos...

The right tool for the job - that's the key - right? Image quality isn't always the top priority. Getting the photo is.