if your gaming on the PC i would recommend MSI afterburner beta. its totally free, is the best graphics card overclocking software available, can display FPS and other stuff on screen like fraps (only more so) it can take screenshots in a variety of formats and, most importantly for you, it can record video for as long as you like in many different formats. it doesnt eat much of my framerate either. you need the beta version to get sound recording, but i havent had a single problem with it
i used to use the free version of fraps, but ive now uninstalled it because MSI afterburner beta does everything that fraps did but it does it a lot better. its the only video recording software that lets me record in good quality, 60FPS and full frame on the graphics intensive games without destroying my framerate. i record in MJPG which makes stupidly huge videos, so i use freemake video converter (also free) to convert the videos into a more manageable size
if your recording something else, such as the xbox 360, you will need a dedicated recorder. if your willing to spash the cash then the best recorders out there are the black magic intensity series and the hauppauge collossus. from what i can see the black magic intensity will be better because it can record up to 1080p, whereas the hauppauge can only record up to 720p or 1080i (1080i is, put simply, 1080p at half the framerate)
