Rock Band 2 or Guitar Hero world tour?

I bought Rock Band 1 when it came out and i also saw the ROCK BAND 2 countdown on SPIKE and ROCK BAND 2 looks amazing but World Tour and it's song creator i don't know what should i pick? I already have Rock Band 1 instruments and if i get ROCK BAND 2 i only buy maybe drums and game. WORLD TOUR whole bundle but still what should i get??? THANKS!!!!!!!!!!!