I bought a Samsung NC10 just before Christmas and it performs really well. Better than Asus EEPC. Has all the usual wifi / ethernet / usb connections. Don't need a CDRom drive. It got a good review on Ch5 Gadget show this week.
Why specifically a netbook (and not a larger laptop)?
And what do you mean 'for GCSEs'? Just typing, spreadsheets, posters? If you just mean this, then any laptop or netbook will be able to do these tasks.