Today's NY Times article, "Seeing No Progress, Some Schools Drop Laptops," marks the end of the first wave of (and roughly, the first decade of) one to one laptop initiatives in schools. On the whole, we've learned that in most cases the benefits, particularly in the age of high-stakes testing, don't outweigh the costs.
In the next wave, we'll have cheaper, more robust and sustainable systems running free software. The cost/benefit analyses will work because the additional cost to schools will be close to $0. How many years will pass in the trough between the crests of the waves remains to be seen.