Barcelona best "TEAM" of all time? Where do they rank?

Well there is no doubt in the class of the current Barcelona team. I can honestly admit that i personally believe they are the best team currently in the world based primarily on form and simply the way they have done their business. After the Super Classico they were calls about this team being the best of all time, maybe...maybe not....but ill give my view on this well built team.
As a unit this team is incredible, they pass the ball well, score plenty goals, hardly concede and dominate majority of their games if not all but there have been great teams in the past that were well built and just as amazing..not so?

• How about Arsenal's Invincibles? The only thing missing was a Champions League for Wenger's outfit that season. That team attacked with as much grace as this current Barcelona team. That team had world class attacking players such as Thierry Henry, Robert Pires, Dennis Bergkamp and ljungberg. The steel in the midfield with Gilberto Silva and Captain Patrick Veira and their best ever defence with the likes of Toure and Campbell and Keown and at the time the ever improving Ashey Cole who could arguably be one of the best left backs in the game. This team was as dominant as the current Barcelona team but may lose out  on ranking in site of the lack of achievements.

• What about Mourinho's Chelsea which he almost assembled all on his own with his arrival. An extremely solid, powerful, fast, strong squad of players that dominated the Premier League for two years and made a few champions league runs. Their first title they only lost one league game and amassed the most points ever in a Premier League season with 95 points. Mourinho had at that time a world class goal keeper in Petr Cech. A line of quality defenders with John Terry, Ricardo Carvalho, William Gallas, Paulo Fereira. The improving Frank Lampard, Damien Duff in his prime, Joe Cole...crowd favourite Arjen Robben, Thiago Mendes, and up top with  Gudjohnsen and Drogba. Mourinho had a top starting 11 and great squad players in which he made a run in a Champions League where he knocked out a great Barcelona team too. Arguably one of the best teams, atleast in the Premier league if not.

•  What about two great Man United teams put together by Sir Alex Ferguson. Firstly the treble winners that held arguably one of the best strike partnerships in the history of the Premier League where Andy Cole and Dwight Yorke scored nearly 40 goals between them for the Premier League. Almost half the goals of the whole team. That team had Man Utd's best goalkeeper of all time most might say( until VDS retires), in Peter Schmeichel. A world class defense at that time in Gary Neville, Denis Irwin, Jaap Stam. A great midfield which Roy Keane marshalled and was accompanied by players such as Paul Scholes, Nicky Butt, David Beckham and Ryan Giggs. Along with the lucky charms of Teddy Sheringham and Ole Gunnar this team won the champions league in the most dramatic of scenes and defeated some of the bests teams in the world on their way to it including Inter Milan at the San Siro, Juventus in Turin and the mighty Bayern Munich at that time. Also they played out two draws against a star studded Barca team in those times. Easily one of the best teams in the history of the game.
  
• Another great Man United team put together by S.A.F as  they were the 2008 Champions League winners with a great mixture of youth and experience. This team did the prestigious double of winner Champions League and Premier League in fashionable style. A team built from a solid foundation and world class defense with players such as Van der Sar, Rio Ferdinand, Nemanja Vidic and Patrice Evra. A strong and workman like midfield with the likes of Owen Hargreaves, Michael Carrick, Darren Fletcher, Paul Scholes, Ryan Giggs and the added youth of Anderson and Nani. The Top 3 was the crowd drawers as Wayne Rooney, Cristiano Ronaldo and Carlos Tevez and these three players were the deadliest attacking players in that year where the three combined for nearly 80 goals for man united. This team was quality all the way round and had a never-give-up attitude that has been instilled by Sir Alex Ferguson. Definitely one of the best teams.
  
• AC Milan have had great teams through out their history and these teams have dominated European Football especially in recent times. Teams built primarily on strong defense and the attacking players with the ability to make great counter attacks they took out all the top teams. From their win in 2003 at Old Trafford in the final of the Champions League against Serie A rivals Juventus to their infamous loss against Liverpool in Istanbul to their triumph in 2007 in their repeat against Liverpool in Athens. There were all great teams with a similar base. With two of the greatest Defenders to play they game in Alessandro Nesta and Paulo Maldini they had a great defensive stalwarts.These two were accompanied by at the time, a quality goal keeper in Dida and the aging but ever present Cafu, one of the greatest ever. With a workman like midfield in Gattusto, Seedorf, Pirlo and the poise of Rui Costa to add to the World Class Duo of Shevchenko and Pippo Inzaghi they really had a good team that took had ability to compete against any team in the world. Adding Kaka to their ranks, they made it to the finals in 2005 and 2007 where they could have been seen as the best team in the world as they thrashed most their teams on their route to those finals, including the humiliation of Manchester United in Italy. The soon to be WPOTY Kaka was emerging as a class act and this team went down in history as they won their latest CL title in 2007 with the same core of Kaka, Maldini, Nesta, Pirlo, Gattuso, Seedorf, Inzaghi. Where do they rank?
  
• Can't have a discussion about the best team of all time and not call Real Madrid. Madrid is a club that have had many great teams through out their history and some stand out for the wrong reasons such as los galacticos. The project that never came to fruition. In my opinion, the greatest Madrid team had been the team under Vincente Del Bosque which took home the last European crown Real Madrid ever won. In 2002, madrid had a team that was built with quality in all areas with players such as Iker Cassilas, Fernando Hierro, Michel Salgado, Roberto Carlos, Ivan Helguera, Claude Makalele, ( madrid hasn't replaced him up to this day) Luis Figo, Raul , Morientes and the amazing Zinedine Zidane who himself won them that CL crown. At that time they had great squad players such as Solari and Guti, the latter becoming ever present and a legend for the club. On paper may not be the best ever but this team was the last to bring great glory to the White House and were predominantly home based players, very similar to the current barca team. Where do they rank?
  
  These are just some great teams in the history of the sport....they are many more such as Los Galacticos built by Perez that on paper must have been the greatest ever but the missed out due to their lack of achievements and ability to play to their ability. Also there were other great Milan teams with the likes of Rijkaard, Van basten, Ancelotti and those old folks.Maybe some of the Ajax teams of the past could be on this list.Where do you rank this Barca team with these teams?