There's still a major flaw with the way everyone is reporting usage.
When you say Wifi On, please make it clearer if you've just left Wifi on but it's not associated with a network, or if it is on and you are connected to a network and are doing your browsing/email/whatever over wifi.
Two different people can say "Wifi: On, 3G: On" and it can mean two completely different things. In the case where wifi is on but NOT associated with any network (it's just searching for kicks) and you're using 3G for your connection, you will get MUCH less time out of the battery. But if they are both on and you ARE connected to wifi, that will very much increase usage time (if you are doing a lot of browsing/email/youtube etc..)
3G always on
Wifi on about 70 percent of the time. When it's on it's connected to a network