I love Toph, but if its a fight to the death, Gaara wins.
Toph is a little blind girl, Gaara is an adult male. It's such an unfair battle... OF COURSE Toph would win!
Toph has more control over earth. While Gaara does have the ability to manipulate sand and create more of it, Toph can also do that, especially as she develops her strength later in the series.