Fairly typical day, except that that I enabled phone service on the iPhone. This test was conducted with my usual rigorous standards, which means I happened to glance at my iPhone data usage around lunch, and ballparked the data transfer. The only thing I can be sure of is the quantity and duration of the phone calls, and that I had them with me all day.
iPhone 3GS, brightness set to ~55%. Wifi was enabled all day, 7:00 AM – 10:40 PM. 3G was enabled between 11:00 AM and 8:30 PM. A single two-minute phone call was placed. Roughly 11MB of data usage while on 3G (several web pages and Twitter using Tweetie).
Final result: At 10:40 PM there was 26% remaining on the battery.
BlackBerry Bold 9700, brightness set to auto. 3G and wifi enabled all day – 7:00 AM – 10:40 PM. Multiple background apps – SocialScope (Twitter) and Twitter for BlackBerry, multiple web pages and push email for 5 different accounts (4 BIS, 1 BES). 5 phone calls were placed, lasting a total of around 70 minutes.
Final result: At 10:40 PM there was 65% remaining on the battery.
Please shave 1-3mm off the thickness of my next device, I obviously don't need a replaceable battery1.
Side note: I have replaceable batteries for the BlackBerry Tour/Storm/Storm2/8900, the BlackBerry Bold 9700, my Mifi, and the BlackBerry 8530. I do not have any spare batteries for any of my Android devices, which would feel like trying to color coordinate my car with vehicles the rest of the highway. The BlackBerry 9700 is the first device I've ever owned where it takes significant effort to drain the battery (<20% remaining). Enjoy the high caliber of writing I produce right before I fall asleep.