Noise is
indeed important, atmosphere being one of the most crucial aspects pertaining to the enjoyment of any sport.
In football though, as I said, the constant ebb and flow of games makes crowd noise indicative and indeed part of the fabric of said game. It forms an innate relationship with what's happening on the pitch; if the game's exciting, the crowd make noise, if the crowd make noise, the game's more exciting.
Even if you didn't watch the links above, this is a really simple example, shows why:
http://www.youtube.com/watch?v=ifN1wHjcT7E Olympiakos fans, being the away fans, try winding up the opposition fans most of the game, making themselves heard and giving their team a boost. Their team has a free-kick in a threatening position, and you can tell what is happening just by the reaction. Anticipatory mumbling, the rise of voices as the kick's about to be taken, the OOOOOh as it goes narrowly over and clap signifying a decent effort. Then back to the chants.
Just by listening to the crowd, I can work out what's happening roughly on an area of the pitch. Add in the numerous chants and it really is an integral experience to most football matches, crowd noise. Same with your games too, I'd imagine. Apart from the general hubbub, there will be variation depending on the action presented.
Vuvuzelas are far more annoying than your usual extra-curricular stuff at a game. They are constant. They remove everything I have mentioned above as you cannot hear the crowd; if it's the odd bell, rattler or a samba band it doesn't overpower the rest of this. Whilst only a few hundred out of tens of thousands of fans might be using them, it just makes the game a drone and it makes everything curiously flat. You may as well watch the game on mute for all the dynamism they produce. Goal scored? RRRRRR Red card awarded? RRRRRR. At the end of the Japan match today, where they picked up an unlikely win, you'd normally hear the screaming of delighted Japanese as soon as the final whistle went. Preceding this, desperate urging from the Cameroonian supporters and nail biting silence from the Japs. But no, it was just RRRRRRRR.
Whilst I still enjoy the games, a lot of the 'flavour' of a World Cup derives from the individual chants and peculiarities of the teams involved; the Germans mass rallys where a megaphoned supporter directs chants and shouts, our own godawful England supporter band. You can make them out at their loudest, but it's not the same, it all fades away into the RRRRR by the end. The USA match, there was a decent section of the crowd chanting 'USA! USA! USA!' which I quite enjoyed, but it sounded pathetic against the RRRRRR's, as does everything else.
I'm really worried that during penalties, which are the best for this type of crowd reaction, it'll just be the droning. The furious whistles and boos from opposition fans, the encouraging roar or deadly silence of the team taking the penalty, the insane noise that follow a save or a goal. Possibly all gone.