If you want to offer a present to a photographer (maybe yourself!), these "Accessory guide" articles might come in handy. I know photography equipment is often very expensive, so I'll start with unexpensive yet very useful accessories.
Today: remote controllers. They start at a really affordable price (a few dollars!), and they are essential in some situations:
- self portrait or group portrait in which the photographer wants to appear
- long exposure shots (especially bulb shots)
- any case in which it is crucial that the camera does not shake while taking the picture
Usually they are categorized by communication type: wire, infrared, radio. You could also categorize them by functionality: only shutter release for the simplest, or advance controls such as timer settings, exposure length or zoom. And some can do a lot more.
Wired remote controllers do not allow self-portrait, unless you use a timer in which case you don't really need the remote... But in general they are the cheapest, and they are a good choice for light painting and motion blur.
Infrared remotes let you take self-portrait, the problem is then to hide the remote, as you need to point it to the camera!
And then, there are radio remotes which are more expensive, but easy to use and more practical.
Last but not least, onOne software presents... the iPhone app! Yes, that's right! This application only works for Canon and Nikon (sorry), and is not free, but it lets you perform many operations. The counterpart is that you need a computer with WiFi connection to the iPhone, and USB connection to the camera to use it (you'd better have a laptop...).
Remote controllers are great for the price, I am sure not every photographer has one, but all could use it!