Really?
Rio was a good but very stupid (naive is probably a better choice of words) footballer, made many costly mistakes still. Van Der Sar had flopped at Juve and was unspectacular at Fulham. Barthez I might give you, saying he was a top player is pushing it a bit though.
As for Berbatov that's pushing it a bit too.
It's going to depend what you call a top player, then. It could become very subjective. But those with medals in the top flight and with a high market value should be amongst them.
Van der Sar was excellent for Fulham. The question marks were maybe whether we've seen his best days and if he's just a stop gap (amazingly, we got 6 great years out of him).
Barthez was coming off the back of a World Cup and European Championship medals, so 'might give' is not at all generous of you.
Rio, whilst young and still needing improvement, was one of the best defenders at the 2002 World Cup and commanded his £29mil fee for good reason.
Berbatov cost the big money, had played in a CL final, won a trophy with Spurs and was highly sought after. That's someone playing at the top level.
Rooney is another. 18 years old or not, every club in the World would've had him, after the year - and tournament - he'd just had. Along with Veron, I'd add Cole, Stam, Yorke, van Nistelrooy, Kleberson, Hargreaves and Tevez.
Some may have improved playing for us, but all were top level players. There's probably more I've forgotten.