I'm getting about 3 days out of mine. No BT use but heavy use of email and browsing and other random data transfers. Only use about 10mins of voice time a day though as I have a separate cell phone for voice calls and SMSs.
I could push 3.5 days I think but I don't think I could get to 4 days.
My colleague who has one of those Windows Smartphone thingy's can't get more than one day and I don't think he uses it as heavily as I do!!
cheers
brace! brace!