FlexGet

While it's not exactly a tool for beginners, FlexGet provides a lot of useful functionality for automating downloads of many kinds, a real swiss army knife. It also has direct integration with downloaders like Deluge, transmission, uTorrent, rTorrent, SABnzb, etc.

Sadly they're still working on the web UI for it, but even in its current form, it's still very handy to have. And since we have SSH access, the YAML config files can still be edited from the command line.

I'd love to be able to move this onto my seedbox...