Blocking websites on Safari (NOT just pop-ups)

I have jumped from Internet Explorer to FireFox to Safari. While IE had its own block list where I could type in site I wanted blocked, and I used an add-on (Leech Block) to block certain websites on FireFox, there doesn't seem to be such an option already built into Safari nor any possible add-ons in order to do this. In the few posts touching on this topic, some people said to set up a new user account to do parental controls, but want to use this for myself. Is there no way, either within the Safari browser or through an add-on (if there are any, since I haven't been able to find add-ons for Safari on the apple website), to block certain websites? Please note that this is NOT about pop-ups, and that I am using Windows Vista.

Thanks!