i did a factory reset yesterday and afterwards, turned off ALL syncs/automatic syncs, did not install any 3rd party apps, cleared my calendar, did not setup any email accounts, decreased brightness to about 30% and the battery last longer than normal.
sure, limiting the phone to calls, messaging and browsing defeats the purpose of the phones capabilities ...but it was embarrassing having to charge the phone every few hours.
You can add your apps back and sync and get email. But I sync at a much longer time duration and as for email, I have 7 accounts and all check every 15 minutes and I can get through a day. Factory reset does help but so does the, 'Bump Charge'. That seems to be where I get the most bang for the buck.
Another thing that you might consider is getting an app called "Battery Booster" from the Market Place. You can configure it to shut down WiFi and Bluetooth when the phone's screen lock activates. When you "wake up" the phone again, the booster can automatically restart your WiFi.
Note: this appears to be broken in the latest release of the app. I emailed the developer and they made the previous release available for download and installation for me. It's working like a champ again.
I use the 1750mah battery, and am a lite to moderate user. I can get 2-1/2 to 3 days on a single charge using the battery booster. I also disabled all of the automatic syncs that I don't have any need for.