I am in the process of adding a new lens to my bag. I currently have three Canon "L" series lenes -- 16-35, 24-70.
As image quality improves with DPP photography, the faults of current lenses are becoming evident. Canon has introduced a handful of new "digital" lenses. The prices of them will make your jaw drop. The new 200mm prime lens retails for $4800. And the 70-200 will be introduced this spring at a cost of $2499 (not bad by comparison to the 200mm).
I'd like to add a telephoto, or telephoto zoom. I could go with the new Canon zoom, or a prime lens (200, 300 or 400). What do you guys suggest?
Adding a telephoto or telephoto zooms for landscape photograhy is not easy. You have to consider several things: what are you going to photograph, how far away will you be from the subject, at what scale do you wish to isolate detail? On top of these "pragmatical" and "artistic vision" factors, you then have to factor in things like: are you shooting from tripod, do you wish to have IS, and so on.
Personally, these days I have trimmed my equipment to bare essentials. I use a 5D MKII with a wide angle zoom (17-40), and a 50D with the 100 L macro. As such, I can use the 100mm lens in the 5D MKII when I want 100mm, or in the 50D when I want longer reach.
For landscape, a telephoto zoom can be handy, but if you want excellent results, you need to carry the heavy lenses (70-200 f/2.8, 100-400), or the lighter 70-200 f/4 (which is a good compromise).