The sheer variety of games you can play on the Nintendo Gamecube is what makes it a great gaming console. From Super Smash Brothers Melee to The Sims, the choice of games for the Gamecube is very rich and you will never get bored with them all.
The Gamecube also has top quality graphics-- startlingly revolutionary for its time-- though not as fine-tuned as those of the Playstations 2 and 3. Its solid consistency in its more than adequate graphics, however, make up for its slightly unrealistic looking appearance. While each game designed for the Playstation series boasts near perfect graphics for only about 1/4 of the game (with the other 3/4 having only depressingly mediocre graphics), the graphics in Gamecube game never waver in their consistent and attractive originality.
On another note, there is a negative side to the Nintendo Gamecube. The fragile lense that appears when you open the top is very easily broken. In my case, I have already broken two Gamecubes this way. So if there are particularly destructive children or pets in your household, I recommend you not buy a Gamecube.