Peripatetic, you have a grip on the focal length/AOV issue, and you explained the 28-135 confusion nicely for this guy newest. One statement, though, a few posts back, I am inclined to question.
You say that the current round of FF cameras--5D, 1DsMkII--push the resolution limits of even the Canon "pro" lenses. The 5D has 12MP and the 1DSMkII has 16MP, true. In fact, though, the pixel density of both those cameras is lower than that of the 20D, 30D, and Rebel XT. In fact, a FF sensor would have to have 20MP to equal the density of those three cameras. It would need 30MP to equal the density of the Nikon D2X. And isn't it the pixels per square inch that would challenge a lens' ability to resolve detail?
Finally, a point for "newest". You've come a long way from your one-lens-fits-all wish, but before you start buying lenses helter skelter, I suggest you just shoot with that kit lens for a while. There is no standard "set of lenses" that everyone needs. It depends on what they shoot. For example, 70-300 is the most popular midrange zoom--primarily because it is a relatively inexpensive zoom. However, for photographers who have been shooting for a few years, and who own a 70-300, it is the lens most often left behind when they go shooting. Why? Too long for portraits. Too short for birds. Too long to hand hold. To short for a tripod collar, so it is front heavy on a tripod.
My wife and I shoot a lot. I use the 17-85 and 100-400 with occasional switch to the Sigma 12-24. She uses the 500mm F4L with a Canon 1.4xII or 2xII extender. Obviously, we must shoot different subjects. I would have little use for her 700mm or 1000mm lens/extender combo,and she would be unable to shoot with the "short" lenses I use.
BTW, the lens you were originally looking for is a Nikon. If you haven't bought already, the D200 with the Nikon 18-200mm VR lens is the ultimate walkaround camera. In fact, someone with no lenses getting into DSLRs would do well to look into Nikon before plunking down cash on a Canon with "only" 8.2MP and no all-purpose stabilized zoom lens.