I've got a cheap bodyfat scale (from Taylor). I liked it at first but I've come the conclusion that it is too inaccurate to be much use. I've also been trying to gain muscle so if I gain weight I want to know if it's fat or muscle or whatever.

There are other more reliable ways to guage how much of your body is fat. I recommend the accu measure calipers, available for not much on ebay, or just a tape measure around the gut.

As an aside I've found it helpfull to keep track of body fat as opposed to total weight and the answer to putting on muscle seems to be to eat a load of protein for a week or two which causes muscle gain and some general weight gain and then return to the usual low carb low cal stuff.

A nice side effect of that sort of plan is it gives you an excuse to pig out on things like Xmas dinner. Just do some muscle building exercise before (can be jumping up and down and the odd push up), eat loads for a few days, diet the fat off and you should have more muscle, at least in theory. You need the calipers or similar to see if it worked in practice.