Pandora and iheartradio for internet radio, songbird for my songs
Aix Weather is my favorite weather widget along with uccw weather widget.
memento widget for when you gotta jot something down quick.
your favorite console system emulator for gaming (i got snes, gb, n64, and psx) also puzzle quest is another favorite of mine
air droid for easy wireless phone management on your computer.
dropbox is another commonly used one for me.
then of course the owal genetic calculator app.....

also there are tons of launchers if you really want to get into customization and how your phone functions, I settled on using nova launcher, here is my s3 home screens and lock. Bring on the color!