I have tried Simple Calendar and Chronos, strongly prefer Super Calendar--a well laid out but info-packed interface, and the developer is always making improvements.
2Day is a nice task manager, does a lot and lets you enter new tasks with voice.
Wiztiles Pro is good tool for adding some customized tiles to your start screen.
UC Browser is a nice alternative to IE, plus charming squirrel logo on live tile.
Fave lockscreen apps: Photostream, LockMix and Wallpaper Patterns
Phonly for Feedly, wonderful app.
Bing apps I like: Bing Weather, Food and Drink <3 <3
Liquid Timer: Does two things-- one basic timer or stopwatch, but an elegant interface. nice app.
OneNote (but I also use Evernote)
Also a setting that I use all the time --under Speech, set "Read incoming text messages aloud" to always on. It doesn't just read them, it announces them, asks you if you want to read them or ignore, then if you want to respond, etc... I use this every day to text back in forth hands free in the car or around the house when I am busy with my hands. When it says "smiley face" in that robotic voice to read an emoticon sent in a text, it always makes me smile.