...Primarily, I shoot landscape and nature (NOT animals and/or birds!), with some architecture and minimal portraiture thrown in...'m looking for suggestions to move to a whole new system—what should I look for? I'd prefer digital, am comfortable with manual focusing primes AND decent zooms, am willing to spend REASONABLE amounts of money, even for a system with one good camera and one good lens to start. I've looked at the M8, the Alpa TC film camera and considered Canikons, but am not happy with either of their lens systems (Canikon, that is!).
I would REALLY like to keep the system digital, both for costs and workflow reasons...
I don't do much landscape work (yet); primarily wildlife. But if I did, and were looking for a new system/camera, my main criteria would be:
1. Lots of MP, the more the better. Lots of MP enables larger prints, and also the kind of fine-detail resolution found in proper view camera print. The current below-$6K choice is between the 16MP Canon and the 12MP Nikon D2X, either of which would be a (slightly) better choice than the 10MP Leica M8. But Nikon is rumored to be contemplating a full-frame version of its D2X, which would scale up to 27MP or so; and Canon is also rumored to be contemplating something along these lines. I'd wait. (There is no advantage whatever, as far as I can see, in full-frame as such (assuming the avaiability of suitable lenses for either format); its only real advantage is more real estate on which to place more MP--at the cost of less DoF, often important for landscape work.)
2. Top-quality lenses with movements (shifts and, particularly, tilts). And, emphatically, mounted on a SLR. Schleimpflug (tilt) focusing with a view camera is an arcane, time-consuming art/science, and would be virtually impossible on a rangefinder like the M8; it's much easier on a SLR, with the ability to preview the image. The current selection of such lenses for a DSLR is limited (Canon has few more than Nikon; but since all automation is lost, it's no big deal to rig an adapter to remount a T&S lens on a different mount). But all currently-available T&S lenses date from the film-camera era, and hopefully will replaced by better-corrected ones more suitable for critical digital photography (the aftermarket Hartblei series, available in both Canon and Nikon mounts, is claiming to have already done so, though I haven't seen any tests yet).
I'd love to own an M8, for candid street and action-orented photography; but I think a large-MP SLR would be a better choice for serious landscape photography. As for lens quality in the Canikons, many of their older film-camera-era lenses don't really cut it with digital; but my experience with recent pro-grade Nikon lenses has been very good, and I'd take some convincing that any similar Leica lens offered any significant advantage (moreover Zeiss is about to come out with some (pricey) lenses for the Nikon mount).