Well, you can use an S-video cable if your TV has an S-video jack (most new ones do). However...TV quality is terrible compared to a monitor. Not to mention that the resolutions usually aren't right, and the refresh rates tend to suck. I've heard of people using the new plasma screen TV's for watching movies, but even those still suck for doing gaming, graphics work, typing, and most other things.
TV's are cheap. Monitors are expensive. If TV's worked better than monitors, no one would by monitors.