uTorrent

uTorrent is a powerful and efficient BitTorrent client for Windows. Most of the features present in other BitTorrent clients are present in uTorrent, including bandwidth prioritization, scheduling, RSS auto-downloading, and Mainline DHT. Additionally, uTorrent supports the protocol encryption joint specification and peer exchange. Unlike many torrent clients, it does not hog valuable system resources--typically using less than 6MB of memory, allowing you to use the computer as if it weren't there at all.