That's more or less spot on in my opinion. Would just make 4 (controversial, for the most part) changes:
Casillas in for Buffon: A year ago I'd have said Gigi, but Casillas seems to have improved even more, while Buffon is just starting to show signs that he's peaked. Definately the best 2 keepers around though.
Kaka in for Riquelme: Firstly, I'll say that I love Riquelme. Aside from Alonso, he's one of my favourite players; I simply love passing. However, I would say that picking him ahead of Kaka is somewhat silly; Kaka's range of passing and vision is by no means far from Riquelme's, and he offers so much more in terms of dribbling, pace and goals. Gerrard should also be in the running here, but misses out for me as he doesn't have that exceptional touch which can be attributed to Riquelme, and Kaka in particular.
Masch in for Senna: Tight one, but I'd go for Mascherano in this team; while Senna is a little more creative, Masch is a touch better defensively. With the players around him, what you really want is somebody who will sit and dominate the midfield, allowing Xavi, Messi, Ronaldo and Kaka to do what they want!
Torres for Drogba: Drogba is admittedly a monster, with the exceptional passers in this team I think the guile and pace of Torres would work better. He's by no means bad at holding the ball up either. Villa would be in contention, as I'd argue that he's the best striker in the world, but he's a little too slight to go up top alone.