Different instruments are cool. You get so many different ideas. For example when you wtire a song or sumthing try to write the guitarlines on the piano and vice versa - you´ll be amazed by how different your ideas will be. its the same with bass and guitar or any other instrument.

however.. me now trying to play guitar and keys at once.. left hand tapping on guitar (playing powerchords) and right hand pianoplaying (we have no keyboarder, so i guess thats the only possible solution) *L*