Eh, for around the house sshfs isn't the best solution in terms of speed. The encryption slows things down considerably. I can't remember exactly off the top of my head, but I think one of the benchmarks of different network filesystems I saw had sshfs at about 2MB/s and NFS and CIFS somewhere around or a little above 6MB/s. Even so, I use sshfs all the time because I'm too lazy to set up NFS (even though it'd probably take me ten minutes at most).
Slightly more on topic, I'm probably going to stick with just SD cards because then I don't have to carry around anything extra (I'm going to leave the same 2 SD cards in the Pandora all the time) and external HDDs would probably be bad for battery life if they don't have a battery built-in. If they do have one, they're going to be even more bulky and that's one more thing you have to keep charged. However, I might at least try out using my old mp3 player (cowon X5L) as an external drive for the Pandora though.
Slightly more on topic, I'm probably going to stick with just SD cards because then I don't have to carry around anything extra (I'm going to leave the same 2 SD cards in the Pandora all the time) and external HDDs would probably be bad for battery life if they don't have a battery built-in. If they do have one, they're going to be even more bulky and that's one more thing you have to keep charged. However, I might at least try out using my old mp3 player (cowon X5L) as an external drive for the Pandora though.