I use all these apps :
Browser : Dolhpin Browser + Dolphin Jetpack (tried FireFox, Chrome, UC, Opera(+mini) Dolphin is the best )
For Music : PlayerPro+FLAC Plugin (has good enough customization options, has an excellent UI, is very light when compared to other players, no bugs )
For Music Streaming : Tune-In Radio
For Video Streaming : You Tube
For Video Downloading : TubeMate
Media Editing Apps :
Ring Maker
VidTrim
For Video : MXPlayer
For Camera :
LGCamera app(as default camera app)
Pro HDR Camera
Cartoon Camera
File manager : ES File Explorer ( the best free to use file explorer, I love SolidExplorer too but it has a few limitations)
Document Viewer/Editor Tools : Documents To Go (I have 2-3 other document viewers/editors, but this one seems to be the smallest, lightest and fastest)
System Tools :
Startup Manager ( excellent way of disabling some not so important startup apps)
CPU-Z (the smallest and the fastest system info/monitor app I've used till now)
Smart Tools
Social Networking and Messaging :
Facebook Messenger
Whatsapp Messenger
Google+
Google+ Messenger
Google hangout/Talk
Talp-Talk
Techenclave Forum Messenger
Fitness App: Sports Tracker
Keyboard : SwiftKey (with English and Hinglish)
Cloud Storage :
Google Drive
Box
DropBox
Remote Networking Tools :
akRDC (lightest remote desktop VNC viewer)
Connect Bot (accessing Terminal Remotely)
Torrent Manager