Apple Watch Apps

(10) Utilities & Productivity:

FlickType, proper keyboard.

FlickType Notes, for note-taking.

WatchChat for WhatsApp, (Supports FlickType.)

Battery Watcher, to check your phone's battery percentage from your watch.

Coyomi, proper calendar app.

‘Complicate It’ for custom text in complications (Watch face widgets).

Countdowns

Shazam, for identifying music. (Owned by Apple.)

Wunderfind, alert you when your phone is out of range.

Remote, lets you control your Mac from your watch (and phone) - much better than TeamViewer in certain ways.

(3) Social Media Apps:

Chrip for Twitter

WristWeb for Facebook

Lens for Instagram

(12) For better health stats:

Fitness Friend

Heart Analyser

HeartWatch

CardioBot

Cardiogram

Activity Stats

ActivityTracker

Pacer

Steps

StepsApp

Pedometer++

MyFitnessPal