Together with handheld stabilizers, sliders are a great option for adding camera movement to your work. As compared to stabilizers, sliders give you smoother shots. Their minus is that they have a more limited range.
For traditional video work, my favourite slider is the iFootage Carbon Fiber Shark Slider S1, which I reviewed here.
For epic timelapses, I use a Konova motorized slider. You can find out all about it here (the article includes a detailed tutorial on how I do timelapses).