In reply to DreadyCraig:
I ride Fire XC Pro folding and think they're great - although I've seen criticism that the sidewalls aren't particularly strong, I've never managed to gash them anywhere. They're best on loose gravel and muddy stuff - I tend to ride smaller tread on drier, harder stuff.
My Sister rides Maxxis High Roller - I wanted a light tyre with low rolling resistance for her that would still give her lots of confidence.
I've also got a set of Conti Vapors, which seem good.