There's an interesting article in cricket blog The Full Toss, suggesting that when the Ashes start tonight, it will be Mitchell Johnson who decides them, and that picking a bowler because he is fast even if he concedes runs is a mistake. It suggests that England have had no problems with some quite fast bowlers (Tino Best and Fidel Edwards of the West Indies were mentioned), but that they have trouble with accurate ones. The suggestion is that Johnson's occasional lack of direction will make it easy to score.
I think this possibly misunderstands Mitchell Johnson's capacity for destruction. When he swings the ball around at more than 90mph, things happen. Yes, Ryan Harris dried up the runs against England earlier this year, but the reason we remember him is that he took wickets. Peter Siddle, bowling from the other end, has always been a 'tight' bowler, but it was Harris' extra pace and movement that made him really dangerous.
I'm looking forward to catching the highlights. Australia on their own grounds should be a handful. Especially with Mitchell Johnson playing.