Download Ninja is a feature-packed, easy-to-use download manager.
Getting started is as simple as copying a link to the clipboard. The program displays a pop-up alert in the system tray, and if you want to download the file, just click this, select "Quick Add", and it'll be added to Download Ninja's queue.
The program can grab regular http links, as well as video and audio files from all the main media sharing sites. It uses up to 10 simultaneous connections to improve performance. If your downloads are interrupted then they can be resumed later, and there's an option to convert downloaded media files into another format (AVI, FLV, MOV, MP3, MP4, MPG, WMA, WMV).
There's a lot of fine control over how the program works. You're able to add individual files to different download queues, for example, and customise when they're allowed to run, as well as limiting their bandwidth. Individual downloads may be added to the front of the queue, if they're high priority, and the program supports http authentication and using MD5 checksums to confirm a download is valid.
If it's too much hassle to keep leaving your browser, no problem - Download Ninja has its own Chrome and Firefox extensions.
Most surprising of all, there's no adware here, no registration, no marketing annoyances, not as much as a "Donate" button or an ad on the developer's site. As the developer says, "Download Ninja is 100% free to use on as many computers as you like".