I think Deportivo play expection to this rule. They aren't the most solid team at the back yet they are in the Semi-Finals of Europe's premier Club Comp. I think to win the CL in this day and age you need to be able to win away from home, yet still when you are at home play stable and make the most of it.
Porto have only won one away game in the CL, I am dumbfounded to see how they got so far but they are a very very very tough side to beat in Portugal. I can't comment much about Monaco. Being an Australian we don't get any French League coverage. Chelsea have a solid foundation at the back. In the next few years you will see is arguably the strongest backine for the future.
Johnson - Terry - Gallas - Bridge
Johnson and Bridge are 18 years of age, Terry 23 with a level head on his soldiers and has captain all over him and Gallas is 26. You have Robert Huth coming through the ranks also who is another creditable defender.
And to add to this you have a world class midfielder infront of 4 in Makelele who holds the midfield as good as anyone. I think Chelsea need to find a man who can fill hes void like a Gerrard when he is injured or mould Scott Parker into playing this role.
2 of the 3 teams you have mentioned there have always been strong at the back and lethal going forward in Juve and Man Utd. I think there problem is just age, too old (Juve and Man Utd) and too young (Man Utd) in some areas. They will be back next year after some spending on the market but as for Real Madrid. I posted a thread on another forum a while ago about there defence and the absence of Makelele.
I was laughed at but now It looks like I was right all along.
Thankyou