Step 1: Measure your laptop
Step 2: Selecting a binder
I liked them both for different reasons. The first binder is a nice rugged looking binder with a heavy duty zipper and a nice camouflaged canvas cover. The cover has lots of pockets and pouches on the outside. This is something that I would take on longer outdoor trips. The pockets are handy for all of the peripheral gear that one uses with their laptop (mouse, usb hub, memory stick...).
The second binder is more streamlined. It has a nice heavy zipper, but does not have any exterior pockets. There is a nice interior pouch. This is the sleeve I will use for bumming around town. It is compact and provides a fair amount of protection.
An added bonus of using a binder for a laptop sleeve is obfuscation. Laptops are stolen all of the time. On the other hand, I do not see many notebook thieves out there prospering. I also liked the irony in using a binder to hold a "notebook" computer.