A video card with HDMI and an HDMI cable usually works best. A DVI cable will work also. However, HDMI can carry video and sound. What kind of a computer/processor/TV do you have? Is the TV 1080p? There are a few different ways to do this depending what kind of outputs the computer has for video.
You need to give some specifics on the TV Model and the Computer Specifics to get the best answer.
I have a computer with Intel MB DZ68DB, Intel i-5 2500K and my tv, Samsung LN40C500 is hooked with a single HDMI cable. I am using the Intel HD 3000 graphics built into the processor.