Best laptop bag? Anything will do guess. I'm not too picky when I'm purchasing a laptop bag. I go for cheap but durable bags that are water proof and could store a lot of things like the laptop charger and probably some CDs as well.
I've got a Ben Sherman laptop bag. I wouldn't be able to compare it to others because it's the only one I've ever had. Anyway, it does the job and has various compartments, some zipped and some Velcro. It's also waterproof (which I think is important) and I think it looks quite stylish even though I've had it for a few months.
I don't know of any particular brands that are substantially better than others to be honest. There might be some on the market I suppose that offer extra protection against any sort of magnetic or x-ray scanners from damaging your hard drive and flash drives. Personally, I just buy the brand name bags that go along with my computer. This last one I ordered was a Lenovo laptop bag to go with my Lenovo laptop.