[spaghetti]

well let me throw two more cents in:
healthy or not, when you cook a traditional dish from a traditional recipe (english or italian or whatever) we should use the traditional ingredients.
A norwegian or dutch traditional dish cooked with olive oil instead of butter could be probably healthier, but it's not the real thing and, in result, the taste would be...unbalanced.
That's why wen I cook northern italian dishes (risotto, cotoletta, tortellini and many others) I use butter, or a mix of butter and extra virgin as Oldsarge said.
This is cause of arguments between me and my wife: she's 100% Tuscan (and 100% olive oil at cooking), while I was born form a northern italian mother whose milk tasted like butter...