Like many others, I live in an area that has less-than-ideal internet connectivity, so having a good download manager is essential. I have been using GetRight for many years, and it still serves me well. It allows for resuming after dropped connections, and also provides segmented downloads to maximise your connection utilisation. The trial version is free, and is not time-limited. Some of the acceleration features are restricted, but it still allows up to 4 concurrent segments. It does integrate with most browsers, providing a dl click-catcher, as well as context menu options to redirect downloads to GetRight. I have no hesitation in recommending this software to any who are having problems with large downloads or ISP/network interruptions.
I have been using a FireFox plugin for a long time now called DownThemAll! https://addons.mozilla.org/en-US/firefox/addon/201