Hi!
Like Mike, I bought Dahon Folding bikes for me and swmbo.
Just a couple of points - if you want to go on rough tracks, mountain bike style ensure what you buy is up to it. Dahon recommends that we lift our bikes up kerbs rather than ride them - its the joints of the folding mechanisms that are not up to rough and tumble. Dahon do produce specialised folding mountain bikes.
Our bikes are basic seven geared bikes - we should have bought bikes with 21 gears as a mountain bike, any hills and we have to get off!
Folding bikes are also not necessarily light weight, if you are considering taking them on an aircraft check the weights.
Folding bikes are a boon once you've got them, they are easy to take on trains so you can extend your range, train out cycle back.
Hope you get sorted!
Steve