I'm opposed to the idea of "technology needs to be given to our kids" as if it were some kind of Recommended Daily Value -- it's a tool, it's a field in and of itself, but it's not something you can just throw at a classroom to make things "better" or kids more "technologically literate".
That was how braindead my highschool was.
But that's just my take on laptops in class in general. Assuming that you'll be doing it anyway...
I've read a lot of good points in the comments here (filter on the router side, not the laptop side being vital) but I figured I'd tell a parable in what happened to me.
In middle school, the computer lab had Foolproof to lock down the machines (a terrible security package, I might add -- really braindead) but there was a very open culture. If you hung out in the computer lab at lunch, and showed actual interest in computers, before long you'd know the magic keystroke to temporarily disable the lockdown (essentially, sudo privileges). And in this way we'd have files and games on the fileserver and play them at lunch; they trusted us, we returned the favor by not causing trouble.
High school was a different beast. They didn't trust us with anything -- and that we were being treated as more incompetent and less trustworthy than our younger selves was a major point of frustration. So what did we do? Circumvent the security in every way we could. Any door they left open, any trick we could pull, we pulled it.
Detente only came when, finally, they improved the network policy with a round of new computers that had Windows 2000 (as opposed to 98) and used proper ACLs -- that were clearly less restrictive in the general case. We could bring in USB keys, run software, but the machines were essentially reimaged every night. This was fair enough to us, so we went with it.
Why break the restrictions? Because they're there. The more restrictive, the more the desire. The more permissive, the less the desire.
But moreover, only a small fraction of kids will ever seriously butt heads against it. In the general case you can lock down the system to the bare minumum. But the kids who do hit the restrictions -- these are the kids you want to know. Trust them. Give them the keys. Help them play. Talk about your "teachable moments" -- treat them with respect and they'll do the same. They're not stupid -- it's not like we suddenly wisen up at 18. You might even change their lives.
The magic key in middle school was Cmd-]
