The two factors to consider in an infrared filter are; the cutoff wavelength (when the filter starts to block light, which are the numbers you've listed in your question) and the sensitivity of your camera to IR.
This question summarises the looks achieved by the different wavelength filters but you need to keep in mind that higher wavelengths require either a more sensitive camera or a significantly longer exposure to produce a usable image.
All digital sensors are naturally sensitive to infrared (and UV), and are actually too sensitive for normal visible-light photography. As a result all manufacturers put an IR cutoff filter in front of the sensor which (unless you opt to have your camera permanently converted) substantially reduces the amount of infrared radiation that hits the sensor.
The easiest way to test how sensitive your camera is to infrared is to point an infrared remote control at it and take a picture of the IR emitter on the control while pressing a button on it. The brighter the spot you see in the picture, the more sensitive the camera is to IR, and the higher wavelength of filter you can use with reasonable exposure settings.