Shamelessly aping MG Siegler, here's a list of apps I used most in 2013. This is from my Android-centric view of the world, and leaving out the obvious ones like Gmail, Play, Maps and Calendar. I'm going for a categorized approach.
Foursquare — love seeing the world as my friends travel through it
Google+ — unsurprisingly
Instagram — I have some very talented friends
Path — it's a weirdly compelling life-journaling experience
Twitter — has gotten steadily worse this year, alas
Any.do — though I spent most of the year with Todoist, liking Any.do's lightweight approach
Evernote — my outboard brain
Google Keep — shopping lists!
Google Now — the most useful app of all 2013
LastPass — lifesaver, repeatedly
Todoist — a fan over many years
Tripit — still useful, though Google Now is eating away at this
Hue — not the greatest app, but the lights have been a great discovery
UP — this device has been a big part of me getting in shape this year
Wiithings — love the Wiithings scales
Netatmo — crazy eccentric app, but fascinating monitoring my environment
RunKeeper — very well designed app that works well
LoseIt — one of the earliest fitness apps on Android and still working great
Amazon — it's bad to have shopping as a hobby, right?
Netflix — winning when together with Chromecast
Plasma Sky — polished and addictive casual shoot'em'up
Reddit — a guilty secret: not sure it even counts as a pleasure
WordOn — nicely balanced word game
Finally, a word about iOS. I still have and use an iPad, but for one thing only: FiftyThree's most excellent Paper app.