Aargh I wish Ronaldo hadn't been so unlucky with injuries. It wouldn't be close...but I'll still narrowly pick him. As complete a striker as any on this list.
Ronaldo was indeed great, awesome even, saw him a couple of times playing for Eindhoven, together with Nilis (talking about a great striker that saw his carreer cut to quick because of a bad injury !! ), who was Ronaldo's favorite btw, ( http://www.voetbalzone.nl/doc.asp?uid=139874 ). But I have a feeling that those who prefer him or other younger strikers are either too young or unaware of the talents displayed by Van Basten from when he played for Ajax until he had to quit @ ACM. His abilities as a striker where of the scale, no doubt the best finisher ever, bar none. Ronaldo was injury sensitive, but not to a small degree because of his lifestyle, at times he was just too heavy to be good for his body. Van Basten on the other hand was just out of luck suffering from a severe and chronic injury which took him out of the game too often and too quick.