You can use a feature in Snagit called "OneClick". This is a very convenient, always at your fingertips way of capturing. It also quietly sits on the side of your screen, out of your way until you need it. :)
One possibility would be to use Snagit's hotkeys to capture on the fly. As long as Snagit is running, pressing the capture hotkey will initiate a capture. The default capture hotkey is the PrintScreen key, but you can customize this if you would like. Additionally, you can create custom hotkeys for each type of capture (video vs. image) by assigning them to a specific profile.