Ok, so every day this coming week I'm going to do some detailed tests (and then publishing them). My campus has 100% WiFi coverage. This is Day 1: Wifi on all day. Consisted of:
Drove to store (so there was 4G at random periods)
Downloaded 10 apps
Watched a couple YouTube videos
Made 3 phone calls
Checked in multiple times on Foursquare (with GPS)
Used Facebook
Took exactly 10 pictures throughout the day (half w/ flash, half without)
Uploaded 5 of these pictures to Facebook and 5 to Dropbox
Email & Google Voice at normal periods
Browsed the Internet for about 40 minutes
My Settings:
Screen Timeout: 15 seconds
GPS: Always on (Only used when apps are using it)
NFC: On
WiFi: Always on
Notifications: Sound/LED/Vibrate
Haptic Feedback: On
Lockscreen: None
At 4% battery life left (last warning):
Coming up next week:
4G Only
3G Only
4G/WiFi On
3G/WiFi On
Tasker Day (e.g. when event in calendar, turn on WiFi)
My Day (Day where I throw out the experiment and tweak it from past days' experience and see what I can achieve)
Overall, Day 1 thoughts: WiFi seems to make battery life pretty great. If I would have left the phone screen off at 4% it probably would have went 30 more minutes on WiFi, the sleep polling with WiFi and sleep mode in general is excellent.