Question

Is there a quick and nice way using linq?

Answer 1

How about:

var most = list.GroupBy(i=>i).OrderByDescending(grp=>grp.Count())       .Select(grp=>grp.Key).First(); 

or in query syntax:

var most = (from i in list             group i by i into grp             orderby grp.Count() descending             select grp.Key).First(); 

Of course, if you will use this repeatedly, you could add an extension method:

public static T MostCommon<T>(this IEnumerable<T> list) {     return ... // previous code } 

Then you can use:

var most = list.MostCommon();