[EVO 4G Q&A, Help & Troubleshooting] brennen.exe:
I've always had "great" battery life by my standards, and I do next to nothing customization-wise. I almost always go over 24 hours, and have had close to the same result on most of the roms I've used.

Current ROM: Burnt Droid

Launcher: Launcher Pro Plus

Setup: Every time I flash a new rom I do the same thing: wipe, flash, boot, initial setup, reboot recovery, remove bloatware (if any), boot, install apps and settings. Like I said, I use LP for my launcher, and have my settings backed up for two-screens, virtual loop, two launcher rows with swipe actions for most of them, LP's calendar widget, and beautiful widgets' smaller home running with weather updates every time I turn on the phone. I only have one other widget running, SwitchPro, and that does nothing but allow me to reload my SD card, toggle WiFi, GPS, 4G, and 3G. Lastly, I have advanced task killer installed but not running-- I open it occasionally just to kill whatever is still open from previous uses, like the browser or maps. Yes, I've seen the arguments about them and I don't care, it has always given me better performance argue with the results blah blah blah.

Usage/Results: I have one spare stock battery I keep in a battery charger at home. I usually swap in my fully charged stock battery around 9~11PM at night and then put it on my bedside table in my room. Sometimes I'll use it in bed to browse the web a little, but rarely more than 15-30 minutes or so. Alarms (three) go off in the morning between 6 and 7am. My weather/location updates every time I wake the phone. I always load up the browser to check the company intranet on my way in to work, so there's ~20 minutes on the net. Music (sdcard) on the drive to work, always; ~25 minutes. While at work I only use my phone for text messages and e-mail when I am away from my desk, so let's just average it out and say I am using the keyboard to type a response for a combined total of ~45 minutes a day. During lunch I will use the browser again for about ~20 minutes; on occassion I will play a game for an additional ~20 minutes. E-mail has two exchange accounts pushing to my device all day long, but I only get about 50 e-mails a day. I use my calendar like crazy, but I probably only create about two appointments a day from my phone. Music on the way home, always; ~25 minutes. Three-four days out of the week I have school or other after-work events, plus church and outings with my wife and son... so let's average an additional hour of web, music, remote desktop, VPN, reverse VNC, Pandora, videos, Bible app, dictionary.com app, voice search, and/or GPS navigation-- I'd say that's an extremely conservative "additional hour". Saturdays I do yard work, which means ~3 hours of music (sdcard). None of this factors in the calls I receive, but I usually only call a few people and always have brief chats, so just throw in 35 minutes a day for phone. I never run out of battery. Even Mondays, my busiest and longest day (for phone), I usually get home with ~20% battery. Oh, I always have GPS and 3G on, and will occasionally turn on 4G if a certain download is large (IE: 70-150MB). I almost never use WiFi, despite it being everywhere I go.

Conclusion: 3 ~ 5 hours of moderate use per day, averaging 26 hours before I needlessly change my battery out with my spare. Needlessly meaning I have anywhere from 10-30% battery remaining. A bit outdated on the ROM end, but here's a post from June with a screenshot.