Upload & Sell: Off
Probably depends on what you want to do with it. For "on location" file storage its probably great, likewise backpacking round south east asia or something. For 5 days hiking in the mountains where weight and size are important, or where you will have extended lengths away from an electricity source, a netbook might be more battery life limited. For both of those you can always just take more CF cards though, which will probably cost less than either the netbook or portable storage device, and weight less.
I've often wondered who buys these portable storage things - they seem very expensive for what they are.