Otakus One-In-All Tool: uTorrent
There's only one thing every Otaku needs next to air and water: Anime. In the last two years the BitTorrent filesharing system has proven to be the perfect choice to get your anime fast and efficiently. Recent studies have shown that more than 50% of all file sharing traffic is caused by BitTorrent clients.
uTorrent is a Windows BitTorrent client written in C++. It has important features like upload bandwith limitation and the ability to get single files from multi-file downloads.
Download uTorrent now.
Animesuki is a great website for torrent files tailored for the U.S. audience which means they only carry torrent files of unlicensed (which generally means: unlicensed in the U.S.) anime.
The site is updated multiple times every day. They also have a large archive of series for you. There is one downside: As far as I know they list english fansubs only.