RE4 was so much about action that it's not scary, it just pumps a li'l but of adrenalyne. Classic RE games had that special and dark atmosphere, it was unique. That is lost in RE4
I'd like, however, a mixture between the two systems, it's cool jumping through windows and all =P
The games that scared me the most were the Silent Hill games. I mean, how messed up do you have to be to come up with those... things?
Dino crisis also scared me back then, good times =) dinos took a lot of bullets to die X_X