What do you do mainly with your computer? I'll just point at some programs off the list ninite.com provides:
-Gimp is kinda like mspaint and photoshop combined and its wonderful for being freeware,
-winrar is a must,
-avast is the best free anti virus protection,
-steam derp,
-audicity is a simple but AWESOME freeware audio editor,
-vlc is for if you watch a lot of movies on your computer, some file formats can only be watched in vlc
-chrome is my fav operator and i recommend it highly
also i use a program called f.lux that changes the intensity of your computer's screen light as the day goes on it, it's nice on your eyes if you're working on your computer late. I recommend all of them because they are free, small (filesize), and pretty simple!
hope this helps :D