If you want to record from Sky, then you don't need a tuner built in to the card.
You need to decide if you want to use your PC or laptop to capture to because it will effect the method used. Because a laptop only has one drive (even if partitioned) that usually runs slower than desktop hard drives and the OS is always running, dropped frames may be a problem if you capture to DV (the best for editing). Capturing straight to mpeg on a laptop should be OK because the bitrates aren't so high but mpeg is a sod to edit.
Also, a lot of the laptop equipment is quite flakey - Hauppauge PVR USB springs to mind: audio sync issue abound!
If you are serious about capturing, then I'd get a decent capture card for your PC - either an All In Wonder based card or a DV capture equivalent. See www.vcdhelp.com
for more details.
If it's just for the occasional capture that you want to watch on TV later, then I'd just but a DVD recorder and cut out the computer. You can always rip to HD and edit if needs be.