Overall it's gotta be Henry. He's just everywhere on the field. Van Nistelrooy may be a better finisher, doesn't cover as much ground or have the all-round ability of Henry.
Henry is more talented but you have to look at it goal wise. V Nistelrooy has scored more in the premiership so I would go for him as the better striker.
No question that Thierry Henry is the more complete player, but that is because he is older. Last year, he came close to winning the various "best player in the universe" type gongs that get dished out annually so the experts seem to agree with the NSC concensus.
But I'm pleased they're both playing in England, and they are both happy here. In an era when so many people whinge about living in this country, it makes a refreshing change to hear about highly paid foreigners actually singing the praises of this country...
In my opinion, Henry is the best player in England, and has been for the last two years. His amazing work rate and ability to set up goals (not just score goals like RVN) is so good it is almost like having twelve players on the pitch.
Arsenal will be in deep trouble if he suffers a long term injury.