Transmission, the new BitTorrent client
While I was a little disappointed with Ubuntu 8.04's native virtualization capabilities, there were several other things I found to like. One of them: Transmission, the new BitTorrent client. Transmission makes life so much easier in many ways, and is leaps and bounds ahead of the old built-in Gnome BitTorrent client, and even BitTornado, which I covered here before.
For one thing, Transmission manages all downloads from a single client, instead of launching a new instance for every download. Transmission also stays in the background so there's little to get in the way of your regular work. As with BitTornado, you can specify which files you want to download and which ones you don't. And finally, throttle control for when you want to control the bandwidth.
The interface is quite intuitive, and I like the integration with the Ubuntu browsers. See a torrent you like? Click and Transmission comes up. Transmission's download are persistent so even after a reboot, you can just pick up where you left off, instead of starting the download all over again.