That makes questions nearly impossible to answer due to the variety of opinions. (Ask a room full of people what the best favor of ice cream is, for example - there is no 'right' answer.) If you read the forum sticky in the Windows Vista forum, though, you'll find a nice list of free security applications, all of which I would recommend. Try them out and choose the one you like best from each category.
what is the best program that i can use to protect my windows vista laptop and is free?