Here is a few more annoyances and fixes with Windows 7 in our school.
As with a few other schools it seems, we have had problems with group policy folder redirection. It worked on our test accounts but as soon as students started logging on on mass they first of all lost the start menu. We use a shared start menu as we have lots of network software that does not get installed on the clients. Also we can remove the things we do not want them to have such as remote desktop. Group policy modelling said it should work fine, as it did with our test users, but it would not work... then it would... no, wait... not working again. In a panic we copied the start menu they should be getting to the location of the mandatory profile start menu (enable hidden folders, then \\SERVER\SHARE\MANDATORYPROFILE.V2\AppData\Roaming\Microsoft\Windows\Start Menu\Programs). This worked as a temporary fix.
Then teachers and students stopped getting their documents. This is also redirected as they all use different PCs and so their documents are kept on the server. About half the people that logged on had their documents folder looking on the c: drive instead of where group policy tells it to.
We found putting teachers on a roaming profile allowed them to get their documents so we then changed group policy to be synchronous instead of asynchronous. This meant longer logon times but now maybe 95%+ logo on without a problem. We did this because on some clients in the event viewer it said group policy has not been applied as fast logon optimization is enabled, it will be applied at next logon. Also logon optimization is not enabled when users have a roaming profile. This suggested Fast Logon Optimization was to blame.
The group policy is here: Administrative Templates\System\Logon\Always wait for the network at computer startup and logon.