Best Free Software for General U

Please submit your articles on the topic:"Best Free Software for General Use"
There are so many free alternatives to the costly software, that can be used on daily basis in multiple categories. Let's share our best discoveries. Freeware should match the following definitions:

1) Freeware - Free software, often written by enthusiasts and distributed by users groups, or via electronic mail, local bulletin boards, Usenet, or other electronic media;

2) Open source - software distributed in source under licenses guaranteeing anybody rights to freely use, modify, and redistribute, the code;

3)Shareware software, free for non-commercial use. This definition does not apply to illegal freeware as cracked software or warez.

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