Firefox plug-ins are the way to go. I use Video Download Helper. You'll find it in the add-on section in their top 10 most popular. Usually next to AdBlock.
I use it to pull movie trailers for my HTPC. My system shows me two trailers from my collection before playing a movie from my NAS. It's like being in the theaters, except I'm in no danger of seeing a trailer for a chick flick.
If there is one thing a remote-controlled, silent and unseeable surveillance/killing machine needs, it’s more whimsy. -- Marcus