Some useful extension methods for strings.

StringExtensions.cs

/// <summary>
/// Extension methods for strings.
/// </summary>
public static class StringExtensions
{
    /// <summary>
    /// Truncates a string using the specified options.
    /// </summary>
    /// <param name="val">The value to truncate.</param>
    /// <param name="maxLength">Maximum length of the output string.</param>
    /// <param name="options">The options.</param>
    /// <remarks>Based on http://www.codeproject.com/Articles/47930/String-Truncation-Function-for-C</remarks>
    public static string Truncate(this string val, int maxLength, TruncateOptions options)
    {
        if (val == null)
        {
            return "";
        }

        if (val.Length <= maxLength)
        {
            return val;
        }

        bool includeEllipsis = (options & TruncateOptions.IncludeEllipsis) == TruncateOptions.IncludeEllipsis;
        bool finishWord = (options & TruncateOptions.FinishWord) == TruncateOptions.FinishWord;
        bool allowLastWordOverflow = (options & TruncateOptions.AllowLastWordToGoOverMaxLength) == TruncateOptions.AllowLastWordToGoOverMaxLength;

        string retValue = val;

        if (includeEllipsis)
        {
            maxLength -= 1;
        }

        int lastSpaceIndex = retValue.LastIndexOf(" ", maxLength, StringComparison.CurrentCultureIgnoreCase);

        if (!finishWord)
        {
            retValue = retValue.Remove(maxLength);
        }
        else if (allowLastWordOverflow)
        {
            int spaceIndex = retValue.IndexOf(" ", maxLength, StringComparison.CurrentCultureIgnoreCase);
            if (spaceIndex != -1)
            {
                retValue = retValue.Remove(spaceIndex);
            }
        }
        else if (lastSpaceIndex > -1)
        {
            retValue = retValue.Remove(lastSpaceIndex);
        }

        if (includeEllipsis && retValue.Length < val.Length)
        {
            retValue += " ...";
        }
        return retValue;
    }

    public static string StripHtml(this string val)
    {
        //Remove any HTML
        Regex htmlRegex = new Regex("</?[a-z][a-z0-9]*[^<>]*>|<!--.*?-->", RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Compiled);
        val = htmlRegex.Replace(val, String.Empty);

        //Remove any HTML non-breaking spaces or other white space from the beginning of the string
        #region Regex Definition
        // ^(?:\s|&nbsp;)+
        // 
        // Options: case insensitive; ^ and $ match at line breaks
        // 
        // Assert position at the beginning of a line (at beginning of the string or after a line break character) «^»
        // Match the regular expression below «(?:\s|&nbsp;)+»
        //    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
        //    Match either the regular expression below (attempting the next alternative only if this one fails) «\s»
        //       Match a single character that is a “whitespace character” (spaces, tabs, and line breaks) «\s»
        //    Or match regular expression number 2 below (the entire group fails if this one fails to match) «&nbsp;»
        //       Match the characters “&nbsp;” literally «&nbsp;»
        #endregion
        Regex wsRegex = new Regex(@"^(?:\s|&nbsp;)+", RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Compiled);
        return wsRegex.Replace(val, String.Empty);
    }
}

[Flags]
public enum TruncateOptions
{
    None = 0x0,
    FinishWord = 0x1,
    AllowLastWordToGoOverMaxLength = 0x2,
    IncludeEllipsis = 0x4
}