string.Replace() is case sensitive. Regex.Replace isn't, though...
using System.Text.RegularExpressions;Obvious, but somehow I keep forgetting it... It'd be nice if string.Replace learned this trick some day.
string myString = "find Me and replace ME";
string strReplace = "me";
myString = Regex.Replace(myString, "me", strReplace, RegexOptions.IgnoreCase);