Here's my 2 cents..
Most of you are saying you can't get anything really decent from the Champion's League, such as a general understanding, but isn't this what that Champion's League is for?
The Champion's League separates the good teams from the bad teams. Teams that do well are the smart enough teams that have enough depth in their squad, like Manchester United. Look how much depth we have, enough to beat Roma and rest our top players for games in our own league. Why do you think English teams can do well in both tournaments? It's because they have enough depth and players to do so. You all criticized before of how Sir Alex Ferguson carries such a big squad, well this is why.
Now, you're probably saying, if United have so much depth, why'd they lose to Milan last year (which was because of injuries)? Well, teams change, like stated above. United, Arsenal, Liverpool and Chelsea have made changes to their squads and made them even better.
United - Nani, Tevez, Anderson, Hargreaves (Pique being called up.)
Arsenal - Eduardo, & others.
Liverpool - Torres, Babel
Chelsea - Anelka
Barcelona have picked up players, but they don't have enough depth to rescue themselves. Sure, they're still in, but they only just made it.