For 400Mhz FSB youll need an aftermarket HSF if you want comfortable temps. You can get a ACF7 that comes with TX-1 pre-applied (pretty much the same as Ceramique) or a Hyper TX or a Hyper 6+ (sale on the egg), any of them for $30.
why use high end thermal paste on a stock heatsink?
if using the stock heatsink, use the thermal pad on it,
if using aftermarket cooler, you can use both artic silver or ceramic.
if you want to overclock, a aftermarket cooler is recommended.
For single core CPU use the blurb as its the easiest and most effective (even for anything if youre lazy/non-skilled).
But for a C2D use a credit card of something to spread it, dont mind the edges too much as theyll get their share once the HSF is in its place.