Evo's battery life is quite good, if you know what the problem is.
So my wife and I both have Evo's. Both of them running DamageControl's ROM. My battery life will be down to about 45% (or less) after about 4-7 hours. Hers will be between 94-97%. This is with not really using the phone except to answer a call or two. Everything is turned on, WiFi, GPS, Bluetooth, Sync, GPS location, etc. All the social and Sprint apps have been removed except for Sprint Navigation. No CPU controlling tools are running, such as SetCPU or OverclockWidget. Though Advanced Task Manager was running in the background to kills apps every 30 minutes, but I don't think that had much of a bearing on it.
At first I though my battery was defective. It was nuts that her phone was lasting so long and mine was being sucked dry. She wouldn't let me take the battery out of her phone to test, so I started looking at what the differences are between our phones. The only main difference between our phones is the number of apps installed.
So based on that guess, I used Titanium Backup to backup all my apps, then proceeded to remove just about all the apps on my phone. Especially any app that might use the network. Though I left wireless tether as that was installed on her phone as well.
I charged up the phone to 100%, left it unplugged overnight, and after seven hours, it still had 98% charge left. So it was an app(s) that ended up killing my battery life. Now I'm using Titanium Backup to start restoring a few apps at a time until I can find out which apps that are causing the large battery drain.