GK -80%-a good choice, Petr Cech is a good goalie, he has a fast response, and he is a good blaster-stopper! But he is a little bit too weak, he was bumped by Stephen Hunt and he needed to wear his black helmet, what a pity! I have some other good choices like Edwin Van der Sar or Victor Valdes.
DF -90%-a superb line, left side blaster Roberto Carlos da Silva is a super free kicker, attacker and he is very strong, even in the old times in Brazil, he bumps on opponents...Haha! But he now 34 years old already. About the center, Nemanja Vidic and Carles Puyol, they can be very good partners, they can help each other, Vidic can help on headers and Puyol is very speedy and he can help Vidic on response. On the right side, Brown, I will only give you a 60%, he is too slow and he doesn't have a good response but he is good on headers, I think that Gary Neville or Massimo Oddo will be a better choice.
MF -80%-Not bad, Cristiano Ronaldo is one of the best Midfielders in the century and he can run extremely fast and he can go round players shoot penalties, free kicks, I will give this choice a 100%!!!!!!!!!! Kaka' is also a good choice, he works very hard, he helps his mates a lot, but I think that you can put him a little bit forward, he can be a partner with a not too speedy but a good passer player like Andrea Pirlo or Stephen Gerrard. Ryan Giggs will be too old for it, I suggest you to use Nani.
FW - 70%-God, please help me!!! Ronaldinho is a very good choice, I give him 95% but......why you are going to use Louis Saha? What a rubbbbish he is, he shots badly, he is very weak......bad passer.......i give him 40% only, you can use Ruud van Nistelrooy or Jan Huntleaar.
GK - ok and a rather good choice in nowadays football as Cech is quite a stable and fabulous keeper who seldom commits foolish errors.
DF - Center half with Vidic and Puyol should be fine. Both are reliable stopper with Puyol falling a bit backward to cover Vidic; Roberto Carlos seems a bit old and may not be as competable as in his earlier career, and you should also be reminded of his aggressive mind in attacking plays that your left back may often left with a loop hole; Undoubtedly Wes is improving significantly during last campaigne but his form varies from match to match and it could be risky at times to play Brown at your right back.
MF - Giggy could provide invaulable experiences to your relatively your Midfield line and it's a merit; I'd rather place Kaka next to Ryan as his pace and skills, as well as his insights on the pitch, are all important to cover Giggs' ageing problem, esp towards the end of match; With Lampard laying back a bit as the engine room and Cristiano attacking on both flanks with his will, you've got a midfield with hefty creativity and support to the frontline.
SS - Ronaldinho should be one of the best choice available in the world.
FW - Saha should prove to be one of the weakest link in the starting line-up especially when one is reminded of his injury-prone record. He's not the kind of centre forward who can create spaces for Ronnie to make the impact, but rather a lone striker waiting for chances in and out the box.