For those who don't need the indestructibility or built-in vertical grip of a traditional pro dSLR like the Nikon D3 or the Canon EOS-1D Mark III--and that's quite a chunk of the pro market--smaller, lighter, and cheaper full-frame models like the Nikon D700 and the Canon EOS 5D and the 5D Mark II are the real workhorses. Plus, their (relatively) lower prices put full-frame shooting in the hands of deep-pocketed amateur photographers.
The D700 comes in two configurations: body only and a kit with the veteran AF-S VR 24-120mm f3.5-5.6G IF-ED lens. With the kit version you end up paying about $300 to $400 for the lens, which sells independently for about $500, but if you're paying more than $2,500 for a camera body, opting for the somewhat middling lens seems a bit penny-wise and pound foolish. On the other hand, it's relatively compact, and replacing it with something superior would probably require multiple, larger, and more expensive lenses.
Though one normally doesn't consider a weight of 2.4 pounds just for the body an asset, it comes up a lightweight compared with 3-pound-plus models like the D3 or Canon EOS-1D line. However, it's still a tad heavier than full-frame competitors like the Sony Alpha DSLR-A900 (2.1 pounds) and the Canon EOS 5D series (about 1.8 pounds). The magnesium-alloy body feels like a Hummer and it's better sealed than the D300, but it's not up to the dust and weatherproofing standards of the D3.
The body design clearly has more in common with the D300 than the D3, and is pretty Nikon-conventional. Almost all settings are adjusted via combinations of buttons and the front or rear dials. On the top left you've got the quality, white balance, and ISO buttons, plus a locked wheel that selects among drive modes (single shot, continuous low, and continuous high), Live View, self timer, and mirror lock-up. This does make Live View operation a bit clunkier than it needs to be; newer models have a dedicated button for popping into the mode, which makes it faster and a bit easier to use. On the top right, the power switch surrounds the shutter release, plus there are buttons for exposure compensation and exposure mode selection (PASM). Nikon provides a traditional status LCD, which displays slightly different information than the viewfinder: it doesn't show metering mode or ISO speed.
On the front left side of the body sits a switch for focus mode (single, continuous, and manual), flash pop-up and compensation buttons, and ports for a wired remote and flash sync cable. There's a programmable function button between the grip and the lens that you press with your right-hand ring finger; you can assign it from a variety of options, but my favorite is probably the virtual horizon, which uses the exposure compensation readout to display off-horizontal tilt. You can also reassign the depth-of-field preview button, which sits higher between the grip and the lens.
One of my favorite aspects of the D700's design--common to all Nikon's midrange and above dSLRs--is the use of switches for directly selecting metering mode (1.5 percent spot, centerweighted, evaluative) and AF area mode (single point, dynamic area, and auto area). You then use the eight-way multiselector to pick your focus point in the viewfinder. It's the same navigation control as on the D3, and while it's quite convenient, I find the switch itself--which you also use to scroll through photos and information displays during playback--just a little too jumpy when I'm moving fast. Still, it beats the alternatives.
Other controls on the back include separate AF activation and AF/AE lock buttons, as well as the usual assortment of playback, delete, info, menu, and so on. As is typical of Nikons dSLRs, the D700 has a two-button format (delete plus mode) and reset (quality plus exposure compensation).
Like the D3 and D300, the D700 provides lots of customization capabilities, including two banks of savable settings with four slots each and a user-definable menu page. As with the D300, your dynamic area options are 9-, 21-, or 51-point AF areas plus 51-point 3D tracking; also like the D300, they're unfortunately buried in the menus. I also like the ability to choose the size of the center for center-weighted average metering. (There are too many options to cover here: download the PDF manual for the details.)