Replacing My Chair with an Exercise Ball!

I've heard great things thus far! But will it tone my tummy? Help burn fat? Etc.?

Also, what about those Waist Slimming Belts that make you sweat? I've heard that they worked for some, not so much for others. 

I've heard people like using them, but it depends - if you aren't strong enough to keep good posture on it all day, you'll end up slumped over, which is going to be bad for your back. It might end up burning a few extra calories, but it isn't going to magically flatten your stomach or anything. At least, that's my guess.

As for the belts - all it does is make you sweat, so you might lose water weight, but it won't do a thing for burning fat. It's like the plastic suits that wrestlers wear before a weigh in - yeah, it gets their weight down, but it's temporary, not a long-term fat loss solution.

Diet, weight training, and cardio (in that order) - the oldies are the goodies.