Just came back from vacations where I used 2.11a (no mods or hacks), with a bit of wifi, 2G on roaming (explains the full-green signal bar) with no data, some calls, few sms and many hours listening to music on poweramp.
Here's the result: more than 3 days of battery =)
As you can see the phone spent a lot of time awaken (15% awaken vs 2% screen-on) but it showed a low battery drop nonetheless.
As you can see, the ROM is showing a great battery consumption with a mild usage.
One thing to note... on the first day the phone was draining the battery rather quickly and I noticed the CPU area of the phone was warm and the task-managers accused a high CPU usage from the media server and Facebook app. Since I wouldn't use the Facebook app on the next days, I uninstalled it, waited for the media server to settle, rebooted and recharged the battery... and that's the result!!! (To be fair, this can't be really used to point the finger at the Facebook app, but in this case, it was clearly contributing to keep the phone awake).