Definitely one of the harder charts to agree on. There have been so many RTS games since the dawn of time which has given the genre a lot of time to mature. Unfortunately, this is also one of its downfalls.
Due to the saturation of the genre, and the tried and tested RTS formula, what worked once isn't quite enough to please fans of the genre in this day and age. Many, if not most RTS games released today are rather lackluster in the originality department or try too hard to break the mould, usually falling flat on their face. Thankfully for us though, some games have broken the mould and stood out from the crowd over the years, really bringing the genre forward in areas otherwise neglected or thought impossible.
The following games are the ones Chart-Box believe have either stood the test of time, or totally redefined the genre overnight. They are held as the best RTS games of all time.