I recommend the Onair GT HDTV tuner, especially if you have the 1920x1200 Truelife LCD. It's USB powered (not AC powered) and a compact unit (about the size of a large desktop mouse) so it's basically made for use with laptops.
It receives and records OTA HD channels. It also has A/V input, so you can play the PS3 with it on your laptop. It also comes with an OEM version of nvidia's Purevideo HD encoder. I use this thing everyday to record my favorite shows.