Vinegar has a virtually indefinite shelf life. Because of its high acidity levels, vinegar is practically self preserving and does not require any refrigeration. Refrigeration won't harm the vinegar. But, if your fridge is short on space, you can pull the vinegar and store it in a cabinet without any worries. I keep my good vinegar stored in old wine bottles on a wine rack arranged by type and age.
What everyone needs to remember is that when it comes to vinegar, "preservation" in terms of safety and "preservation" in terms of quality are two different things. While vinegar may have a practically indefinite shelf life when it comes to safety, many vinegars do not have an indefinite shelf life when it comes to quality, especially in terms of taste and color.
The typical vinegar that we buy in the grocery store will last for a very long time. They have high acidity levels that prevent bacteria and mold growth. Vinegar such as red wine vinegar typically has sulfites added to preserve color. These vinegars do not require any special treatment or refrigeration.
Balsamic vinegar, on the other hand, tends to be sensitive to light, especially sunlight. The general rule when it comes to balsamic vinegar is to store it the general way you would store red wine, especially if the balsamic vinegar is high quality. A temperature-stable, dry environment away from sunlight is ideal for balsamic vinegar.
When dealing with shelf life in terms of safety, some vinegar can go bad over a period of time. This depends upon the type of bacteria used to make the vinegar. All bacteria used in the vinegar making process produces vinegar by consuming alcohol. Most bacteria simply die when the alcohol is gone. However, some bacteria can consume acetic acid in place of alcohol in a process called "overoxidation." In this process, the bacteria consume the acetic acid and produce water and carbon dioxide. Over time, this process slowly dilutes the vinegar lowing acidity levels potentially to the point where other bacteria and mold can grow thus ruining the vinegar. However, most typical store-bought vinegars are not made with these types of bacteria.
Its interesting to point out that vinegar that does not have additional sulfites added can change color over time when exposed to light through the Maillard Reaction, which is a reaction with which all of us should be very familiar.
So, at the end of the day, the general rule is that the more "exotic" (and thereby more expensive") the vinegar, the more care is required to ensure its preservation. However, even with rare and exotic vinegar, we're still not talking about complicated storage processes. Simply storing the vinegar in a proper, air tight container such as glass, and storing it away from sunlight in a place where the temperature does not fluctuate is pretty much all that's needed. For most vinegar, your cabinet is ideal.