hdmi lead from laptop to the hdmi on the tv ,my 5yr old LG tv has one so if you have a fairly modern tv it should be ok.......
I got my lead from ebay for £1:50 and it works fine.
Depends what you have on the back of the TV. I've used a 9 pin cable before now as this fits into where you'd connect the laptop to a projector and my TV happened to have a 9 pin input.