We had a similar poll like this, eons ago, which I revived one day viewtopic.php?f=13&t=158822&hilit=greatest+soccer
Of the teams you mentioned, I think Ajax's 12 Apostles was the best ever. Long live Johan Cruyff and total football.
I have a heavy disdain of Real Madrid, but the sides of Di Stefano and Puskas are up there and the same for AC MIlan when they had Gullit, Rijkaard, and van Basten.
Instead of Real Madrid 2002, you should've put Barcelona's '92 Dream Team as an option. Manchester United's 1999 treble side over Liverpool; remember Liverpool's treble campaign was derailed when United upset them in the 1977 FA Cup.
So, here's my top 5:
1. Barcelona 1992
2. Ajax Amsterdam 1971-73
3. Real Madrid 1956-60
4. Manchester United 1999
5. AC Milan 1988-89