I really can't claim to recommend anything, having only used the camera in-store for less than half an hour; all I can say (again) is that Fuji Guys recommend Class 6 at least, and that personally I've only ever used SanDisk cards professionally, and always their Extreme series. Never had a problem - but that's not to say they'll work as flawlessly with this camera as they have with 1-Series Canon bodies.
The Toshibas may be faster, I couldn't say; but if they're listing their maximum speed vs. Sandisk's average or minimum guaranteed speed...also, have the Toshibas sacrificed Error Correction Code (ECC) for speed? I have no idea, I'm just asking.
Frankly, what I'll probably wind up doing is buying a newer/bigger SD card for one of my Canons, and bumping the SD card that's in there now down to the X100, now that I think about it. Which likely means I'll be using a Sandisk Extreme III 8GB Class 6 30MB/s card, until / unless I run into some kind of problem with that. (That said, it's VERY unlikely I'll be shooting video on the X100, so I won't be taxing the card's speed in that particular way.)
Hope that's some kind of help -
R