Personally, I think I might prefer a hard case for devices like the Nokia N810 but those seem hard to come buy. There are only a few cases at all that I have found that are designed to fit the Nokia N810 and they are all leather cases.

Within the leather case options, the main choice seems to be whether you want it to open horizontally or vertically.

Personally I would chose the Nokia N810 horizontal flip cover because it seems like there would be less flopping around when the case was open.

Having said that, it looks like with either version, you will have to remove the Nokia N810 to actually slide out the keyboard to type. If that is true, than it looks like the vertical flip cover might be user when removing the device.

Either way, both have a place for credit cards and money and memory cards in the part of the cover that you flip open and a secure spot to store the stylus.