Another thread asking for people to post OTA update problems noted that a few people had to re-install google maps (I did not) - but - with the update, google talk is now coming up and babbling.
Open it explicitly, and tell it - via prefs - to not autostart on boot. That's a resource waste right there, especially if it's not being used.
Ditto on GMail - I get my Gmail via the Mail app along with my other mail accounts. I went to Setup -> Applications -> GMail and cleared all of its defaults. It gave me a scary dialog, but I just went for it anyway.
Then I powered down and up.
11 hours later, with light use of my phone, I've only used 21% of my battery from where it was when I re-booted - and my google maps are faster than ever. (edit - wifi's been on a full six hours, not so much on the mobile data net)
Everything's working.
So is my active wallpaper, by the way - so much so that I might drop that - although I'd rather not.
I run the rooted version of this, so your mileage may vary, but maybe those suggestions will put your Evo in the green again.