To be completely honest, every instrument in the woodwind family carries as much weight as the other. A Flute can cover higher, faster runs, where a Bari Sax provides the pumping bass line. An Oboe will sign melody as the Clarinets bring warmth to the music behind it. read more
The biggest/lowest instrument in the standard woodwind family (meaning it is used in most orchestral scores) has to be the Contra-Bassoon, or the Double Bassoon as they call it in some countries. The absolute largest instrument in the woodwind family is the Contrabass Saxophone in Eb. read more