Quite often I find myself wanting to check in a petite way if an enumerable is empty. Instead of having to do:

bool notEmpty = myEnumerable.GetEnumerator().MoveNext();

Using linq you can simply use this System.Linq.Any() extension method:

var notEmpty = myEnumerable.Any();

I´m often afraid to overuse linq since some of the commands could end up iterating the entire enumerable to get your results, like writing:

bool isEmpty = myEnumerable.ToArray().Length == 0;

The above could definitely give a performance hit if placed in an unfortunate codeblock.
However, reflecting the Any() method gives us:

public static bool Any (this IEnumerable source) {
    if (source == null) {
        throw Error.ArgumentNull ("source");
    } else {
        using (IEnumerator enumerator = source.GetEnumerator ()) {
            if (enumerator.MoveNext ())
            return true;
        return false;

In other words, it just compresses the first codeblock I used in a neat and understandable manner.

Enumerate away!