Mose of these are for use with a PC, but many of them have Mac alternatives.

1. WinRar (info / install 32-bit / install 64-bit)
   WinRar is the best program to have for packing and unpacking .zip, .rar, and .tar files (as well as others). It makes it super easy to archive your files.
    
2. IrfanView (info / install)
   This is a great free photo/image editor program, but what I actually use it for is bulk renaming or editing of photo files. It’s particularly useful for resizing a folder of 500 photos all at once. Not to mention it has some pretty awesome editing abilities.
    
3. YouTube Downloader (info / install)
   Did you LOVE that YouTube video you just watched? Download it! You can also convert downloaded videos into .mp3 files, so if you just want the song from a video, there you have it. (Note: I do not recommend using this program for illegal purposes)
    
4. BitTorrent (info / install)
   Similar to Frostwire, but safer, faster, easier, and better. Not to mention there are all kinds of useful files (ebooks, for instance) out there waiting to be downloaded. For finding files to download I recommend using thepiratebay.org. (Note: I do not recommend using this program for illegal purposes)
    
5. Mp3tag (info / install)
   See all of the information that is attached to your .mp3′s (and other music files) and edit it. Includes more labels than you would ever, EVER use. My favorite one to edit is the “comment” section which often has weird things in it like people’s websites, or Amazon file codes.
    
6. Dropbox (info / install)
   Dropbox is the best and easiest way to synchronize your files between computers or with a friend. You can also upload files to a public synchronization server and share with friends.
    
7. Evernote (info / install)
   Organize your photos, recipes, poetry, grocery shopping lists, contacts, .pdf files, artwork… everything imaginable! All in one place, all searchable, and syncable with every system (laptop, cell phone, iPad) you have… It’s amazing.
    
8. Glary Utilities (info / install)
   Super simple, super effective, super fast computer optimizer and virus checker. My favorite one to use on a daily basis. It literally takes less than a minute.
    
9. Advanced System Care (info / install)
   Another computer optimizer and virus checker that is a little more advanced and involved than Glary Utilities. Speed up your computer! Fix those bugs! It’s easy! And free.
    
10. Malwarebytes Anti-Malware (info / install)
    As it states in the title, this is an (extremely effective) malware/spyware remover. I only use it about once a month, or whenever I get a Trojan or bad virus.