I picked this up today (thanks to Best Buy Bucks! God, I love these things!) - the Rumble Pak really isn't louds... Maybe I got an odd one, but it's pretty quiet and not really a big deal - in fact, I was a little disapointed in how.. almost unnoticable it is...
It's a pretty fun game though... There doesn't seem to be a "lot" to it, but it's fun.