Your cell network may be partly responsible for battery drain. Here in the Netherlands I was on the T-Mobile network, and the last couple of months, after 18 hours of use the battery was still about half full.

I switched to Vodafone recently, and immediately the first couple of weeks I could hardly get through the day without recharging! That really sucked, and I was a bit upset at having a 12 month contract with this behaviour. However, over a weekend the battery suddently started lasting longer again, it's now the same as when I was on T-Mobile.

Apparently there's some sort of powersave mode that the cell network operator can engage. I do (subjectively) find that connections take a second or so longer to establish now compared to when the battery ran down quickly, but that's worth it :-)