"A free download manager from websites like Rapidshare or Megaupload."
The Rapidshare.com and Megaupload.com websites are used by thousands of users to up and download files. That makes a tool like Jdownloader really useful. It is a download manager that's totally free for websites like these.
This way, with Jdownloader you can speed up, optimize and simplify the download process from these websites. To use it you just need your corresponding accounts (both Premium and free). You can do multiple downloads at once, and it has many simultaneous connections. It also has tools to administer passwords, automatically extract files, etc.
As it's an independent platform, Jdownloader not only works with Windows, but also with Linux and Mac. It has its own decryptor (for those web downloads that are encrypted), its own OCR, decompressor, etc.