One of the most difficult lighting situations you can encounter in photography is a macro shot. Since the depth of field becomes so shallow when shooting close up with a macro lens, you often end up having to shoot at very small apertures (the ones with higher numbers, such as f/22 or f/36) if you want more than just a small sliver of your subject to be in focus. This means you need a lot of light on your subjects. At the same time, since you're usually so close to your subject, it's easy to block the light from whatever you're using to illuminate the scene. The typical solution for macro lighting is a ring light, which mounts to the front of your macro lens and is tethered by a cable to a controller unit mounted in your camera's hot shoe.
However, with ring lights you're limited to a handful of ratio settings between a pair of strobe heads built into the ring light if you want to vary the look of the lighting. Nikon's R1C1 Close-up Speedlight Commander Kit includes a pair of small SB-R200 flash units, along with an SU-800 wireless trigger, so you can place the lights wherever you need them, including the mounting ring that comes with the kit, and control them from the trigger that mounts on your SLR's hot shoe.
If you don't want to use the ring to hold the R200s, you can also mount them on the stands included in the kit. The stands won't work with larger Speedlights, but they do have tripod sockets in the bottom, so you get an added level of versatility in placement, especially if you mate them with a GorillaPod or other similar device. The kit also includes other accessories, including adapter rings for various lenses, a set of four colored filters, filter holders, a flexible arm with clips at either end, a diffuser panel, clip-on angled diffusers for extreme closeup work, a panel to block an SLR's built-in flash (more on this later), soft cases for the flashes and trigger, and a case to hold all the pieces. While the big case is a bit clunky, it does include room for a third SB-R200 and all accompanying accessories for it, should you choose to add one.
The SU-800 can control as many as three groups of flashes on each of its four channels. For the uninitiated, the channels are there so you can work in the same area as another photographer that is also using Nikon wireless flashes; as long as you're working on different channels, you won't fire each other's flashes. The groups let you lump together multiple flashes and control their output separately from the other groups in your setup. So, if you have group A on the left, group B on the right, and group C behind your subject, each of those groups can output a different amount of light, so you can sculpt the light across your entire scene.
While there are other macro lighting solutions on the market, Nikon's R1C1 kit is one of the easiest to work with and provides more flexibility in placement and control than any other kit we've seen. Add to that its expandability and compatibility with other Nikon flashes and it even becomes hard to fault it for its seemingly high price tag. If you already own an SU-800, or plan to use your camera's built-in commander mode to control the flashes, Nikon also offers a version of this kit, called the R1, which includes everything in this kit except the SU-800. However, I wouldn't recommend using the built-in commander mode instead of the SU-800, since I found it much easier to deal with its controls instead of the ones in the D2Xs (the D40X doesn't have a built-in commander mode), and wouldn't want to limit my number of groups or channels. Since no other manufacturer has seen fit to copy its concept, the R1C1 kit is one of the accessories that sets Nikon apart from the competition. For anyone who does a lot of macro shooting and isn't tied to one brand, or is considering a switch away from one of Nikon's competitors, this should be a major reason to consider a switch to Nikon.