Laptops / Netbooks for school use

I'm looking to buy 30 netbooks for use within the Maths Department and 20 laptops for video editing/graphic design.

We currently keep our laptops in Lapsafe Trolleys and i've found that constant recharging throughout the day has resulted in depleted battery lives. I've also got issues with pupils pulling off keys.

Does anyone have any advice/experience on purchasing and using laptops and netbooks in a school environment? I'm looking for laptops and netbooks that are durable enough to be used frequently by teenagers and have batteries that would last the full school day on one charge.

Also, which laptops, within that criteria, would you recommend for video editing?

Thanks

I think most the of networks these days have battery life of 6+7 hours.

I personally like the samsung ones :D

As for video editing, id be surprised with an activity like that, battery life would last more then 2/3 hours without being the need to be charged