I joined the cult of Steve Jobs with early 2011 MacBook Pro. Mac OSX comes with a host of default apps that do a great job for normal user. But if you are edging towards a power user this apps might come in handy.
Most of the apps noted below are free and I use them often. If you have any apps you would recommend, leave a comment.
General Apps:
Text Editor : TextWrangler
PDF Reader : Skim
App Uninstaller : AppCleaner
Archiver Utility : TheUnarchiver
Video Format Convertor : HandBrake
Audio Format Convertor : Audacity
Video Player : VLC
Bi-directional file synchroniser : Unison
BitTorrent Client : Transmission
Magic Mouse/ Track Pad utility :MagicPrefs
Book manager : Calibre
Notes taking : Micorsoft OneNote
IRC Client : Colloquy
X Windows support for Mac :XQuartz
Terminal : iTerm2
Package Installer : HomeBrew
Package Installer : MacPorts
Video Podcastring / Recording : OBS
Photo Organiser by Metadata : DateTree
Skill focused apps:
MySQL Client : Sequel Pro
Regular Expression builder/tester : Reggy
Network Simulator : GNS3
Network Packet Analyser : Wireshark
Netmask Calculator : IP Calculator
Photostream photo copier : PhotoStream2Folder
Audio Metadata Editor : Kid3
Virtualization Software :VirtualBox
IDE : Visual Studio Code
Photo Editor : GIMP
Skill focused nonfree apps:
Modelling tool : Visual Paradigm (Community Edition)
IDE : IntelliJ IDEA Ultimate (Has free community version)
Drawing tool similar to Microsoft Visio : OmniGraffle
Photo Editor : PhotoshopCC
Photo Manager : LightroomCC
Password Manager : Wallet
Password Manager : PwSafe
Personal Accountant : iBank
SQL Client : SQLProStudio
Web Design Tool : BootstrapStudio
BluRay Burner : ExpressBurnPlus
Personal Diary : DayOneClassic
PDF Reducer : PDFSqueezer