I have an extended battery and it still doesn't make it through the whole day
Keep in mind that a Droid Incredible with the 2150 battery has longer battery life than any smartphone by a long shot. If you still have battery issues, then your problem is not the device but a severe software configuration issue.
The first thing I will say is that by default the software configuration on the Incredible is extremely battery intensive. It is in no way a configuration I would suggest anyone remain with.
Widgets suck up battery. By default there's quite a few widgets open. The friend stream widget itself uses a TON of juice. Consider using the Android Facebook app instead. Only use widgets you absolutely need.
Google Talk is set to sign in by default. If you don't use it, set it to not sign in when you turn on the phone.
Consider closing the weather widget and opening a weather app when you want to know the weather. Also set the weather app to not sync in the background, have it update weather info only when you open it.
Other apps you have installed might have "run on startup" configuration settings. Fring does. Disable these and only open the app when you need it.
For the apps that you must keep data sync on with, consider making them check for new data less often.
Disable Flash in the browser. Enable it only when you need it but remember to disable it again afterwards.
Under no circumstance should you keep any kind of instant messenger app like AIM or Ebuddy or Meebo open at all times. These are very battery inefficient because of a very constant data stream. Use them when you want to chat but then shut them down when you're done.
Change the screen setting away from auto brightness and then set the brightness to 30-40%. You will find that it looks perfectly fine at such a setting and you'll get better battery life.'
Refrain from using live wallpapers. If you really really want to stretch your battery, set your desktop background to a blank black picture. The OLED screen uses less power displaying black than anything else.
Turn off as much vibration as you can. That motor can really suck up juice if activated a bunch over the course of a day. I turn vibration off for the 4 main buttons, typing, and in all games that have it. I leave vibration on for calls.
Those are the tips that I can think of for the moment. Android is a fully customizable operating system that does not hold your hand. It will let you run anything you want at any setting without warning you about the consequences.