Yeah, I wish I could use wifi at work.
I've been using Tasker the last few days to shut my mobile data off after the screen has been off for 5 minutes. It's saved me around 10% more of my battery during a work day. I still can't believe this isn't a built in setting like it was on the Droid x. Now I can pretty easily make it through an entire day without charging, whereas before, sometimes it would be about to die right before I go to bed.
I guess juice defender does the same thing but it turns off as soon as you lock it, so if you lock/unlock your phone a lot like I do, it will burn through your battery even faster.