We need to replace our library's netbooks.

The question is, do we get netbooks or laptops? They all seem to be a similar price on the market now (or little difference).

My list of pros and cons is;

Netbook Pro's - small, portable, should hold battery life longer
Netbook Con's - generally smaller processors, not really capeable of running certain softwares smoothly (we have trouble with movie maker on the current ones).

We are concerned mainly about battery life though. Whatever we buy will be used essentially for about 5 hours a day (in a row) - with potential chance to charge in the middle (lunchtime).

All of the laptops/netbooks I have seen in our price range (200-300) have an advertised battery life of about 5.7 hours. (I know this will be exaggerated!).
But what is the total life of the batteries like? We need them to last for about 5 years, and the ones we have now, after 5 years of use, are pretty much useless - they don't last 20 minutes anymore.

So, what do you all use? Any recommendations for or against?