I think, assuming it exists, it should have Openoffice, and other free software. It should also give students admin rights, but operate on something more obscure to the majority of students (Linux of some kind?)...this is to allow the more computer-oriented students to experiment, install programs, etc, but stop problems like viruses.
It should have
At least a 10-inch display (if it has external connections) or 14 if not
Laptop/netbook preferred as the Tablet market is not super established yet - although a Xoom could alleviate a lot of problems - its open-source and gives admin rights, but is obscure enough to avoid most viruses, general stupidity.
Should have at least 2 (prefer 4-6 USB ports)
Firewire port
Both in and out sound ports
802.11b/g/n
full sized backlit keyboard (for those late-night essays)
dvd/cdrw drive (preferably internal but I guess external is OK)
Easy-To-upgrade HDD/SSD, ram
decent processor (>2.4Ghz, dual core)
As a student who rather likes technology, I do not think that schools should give out laptops. I am not sure if this is an attitude shared by many, but I would feel nervous about using it on my newtork as it would obviously have some kind of a "big brother" program installed. In fact I probably would refuse to use a school-issued computer whenever possible...

... Even an application I would have some worries about installing... (yes i am a bit crazy about other people + my data... regardless of how insignificant it is...)
Perhaps a better option is allowing students reduced prices on certain models of laptops, or free software licences for major programs. If you did give out hardware though, please make it 1) major/standard brands (not off-brands) and have major software without monitoring software installed.