Samsung Galaxy S3. Had it for almost a year now.
Before that it was some basic flip phone (though had unrivaled battery life against smartphones. Would easily last a week before needing a recharge).
[Edited by Neo7, 4/26/2013 9:33:04 PM]
That is easily the biggest pro to the earlier model phones, i remember the Nokia 3315 was my phone back in the day and it's battery was like that too.
I damaged my S II battery over time by having it in my pocket while welding and i ended up buying one of those huge extended life batteries instead of a standard replacement, that came close to tripling my battery life though i'm not sure on what extent my battery was fried to before the swap.