I originally used bittornado as that seemed to be most popular. Depending on the number of torrents you want running will dictate the amount of ports you forward and the number of torrent windows open. I switched to uTorrent as it only requires 1 port, doesn't need java to run like Azureus but does everything the same. Allows you to que up as many torrents as you like and they'll be processed based on the up/down settings. Shows enough statistics and seems to work very well.