A reasonable controller will have 512 channels, which is more than you'll need but will support pretty much any light you might want to add in the future. Chances are you'll want several lights assigned to the same channel anyway so they are synchronised. Each light will need a certain number of channels depending on capabilities - an RGBW scanner will need a lot more to control the individual colours and X/Y movement then a more simple fixed RGB flood.
I don't use a foot controller, it's a box with buttons and sliders. I have created a couple of programmes - a changing 2 colour wash for while we're playing and a single colour dim wash for the breaks. The controller has sliders to control the cycle speed and cross-fade time, that I ramp up as the night goes on, or a sound to light mode for the more frantic bits towards the end. It also has a blackout button. It works quite well especially after I added another light that shoots beams of light around the stage - which gives a bit of movement even if we don't have space to jig about much ourselves