I don't have many android apps but few I'm using:
Facebook - rather using that than using browser for checking FB..waiting for events feed tho :P

Youtube - video/audio is sometimes badly out of sync, sometimes not, only using randomly, mostly for listening some songs.

Firefox for browsing
Shazam for recognising songs
Tapatalk for reading forums.

Thats pretty much it. I would probably use more if I bothered installing google play, got lots of apps there.