The Apple trackpads are large at 5+ inches and responsive and reliable. I love mine. I had multi-touch and gestures hacked into a Linux driver on my old Dell five years ago but it was never nice like this.

And Apple also makes mice that do gestures and multi-touch on the touch responsive top surface.

Gosh, I sound like a fanboy here but I really despise the fruit-based company for their evil corporate practices. You just can't beat their hardware, though.