OK, so I've had the extended battery for about 10 days now, and overall, it's a big improvement over the standard battery. As many have said, it adds almost nothing to the thickness of the Droid 2. Even with the extended battery, my Droid 2 is still amazing thin next to my Touch Pro2.
People who claim to be "heavy users" are claiming the standard battery is sufficient, but I can't imagine how those people can be categorized that way. I use my phone for business, and I am on the road for a good portion of every day. Some people are claiming 32 hours off the charger with the extended battery, and in my opinion, they didn't need the extended battery to begin with.
With the standard battery, I took my D2 off the charger at 7:30am, and was at 15% by about 2-3pm. The extended battery has yielded far better results for my use. I am now able to take my D2 off the charger at 7:30am, and I don't hit 15% until about 9pm.
I have been a smartphone user since 2004, so I know about battery management. The fact is that my Touch Pro2 would consistently last a full day (my definition would be 15 hours) with the standard battery. I know that Android demands more battery life, and I never used things like Pandora with my Touch Pro2 (not by choice of course). Not to mention widgets, etc. The only things that auto-updated on my Touch Pro2 were push e-mail, weather via HTC Sense, and my Twitter acct. This is far different in Android.
I guess putting some solid numbers behind my average usage will help too. My average day consists of:
~ +/- 100 minutes of talk time (yesterday was 126 mins; day before was 97 mins)
~ +/- 160mb of data/day (about 4.8gb/month)
-Pandora
-Beautiful Live Weather (set to 30 minutes)
-I Heart Radio (gotta love listening to Mark Madden from 600 miles away!)
-A little bit of Kongregate while waiting for clients
-4 e-mail accounts set to push (or 15 minute update intervals)
-Facebook / Twitter updates to my business pages
-11 RSS feeds
-NFL Mobile (streaming highlights, reading news, etc)
I also have my screen set to auto by the way.
I have come to expect charging my phone every night, as I've been doing it for 6 years. Therefore, 13-15 hours suits me just fine.
Just thought I would share.