uTorrent

While I'm not a big torrenter I know some who are and I think the protocol is fantastic. I've used it myself to quickly and easily send large files to friends and colleagues. Mac users have had realtivly few choices in a torrent client, though we've always had access to the arguably best one Azureus. It's packed with features and based in Java so it runs on just about anything. It's also a little bloated and packed with features many don't need. Rumors are that uTorrent is making its way Macside and the net is abuzz. Many Windows users swear by this client for being fast and lightweight. I may test it out at some point after its release next time I need a linux image or something.