Are you crazy? The iPhone 4 has one of the best (if not the best) battery life numbers in the smartphone segment.
No I'm not, but you certainly must be. Either that or you're desperately uninformed!
Iphone 4
BATTERY Standard battery, Li-Po 1420mAh
Stand-by Up to 300 h (2G) / Up to 300 h (3G)
Talk time Up to 14 h (2G) / Up to 7 h (3G)
Since I own this I can tell that these numbers are false and you'll be lucky to get 6 hours of talk time out of it with an average standby time of 48 hours.
Lets see how others do though:
Nokia E6
BATTERY Standard battery, Li-Ion 1500 mAh (BP-4L)
Stand-by Up to 681 h (2G) / Up to 744 h (3G)
Talk time Up to 14 h 48 min (2G) / Up to 7 h 30 min (3G)
Samsung Galaxy SII - Dual Core
BATTERY Standard battery, Li-Ion 1650 mAh
Stand-by Up to 710 h (2G) / Up to 610 h (3G)
Talk time Up to 18 h 20 min (2G) / Up to 8 h 40 min (3G)