PCMCIA will come with limitations. though it is expected that both will eat up equal amount of power. assuming that, i would have gone for a USB one, becuase, you may find is with more features (external box), also, you dont have to stuck in fat antenna cable to the PCMCIA, which in that case, MAY effect your antenna port as when you have to move the laptop.
Hauppauge (I hope spellings are correct), USB2-PVR (PVR stands for Personel video recorder in this case. (assumption). this can record in MPEG format as well. and comes with bundle of features. rest, check out with other people using TV-Tuners.
Intel Core2Quad 2.66Ghz 12MB L2-Cache
4096MB DDR Kingston Hyper-X
XFX 9600GT AlphaDog
Seagate 2 X 320GB SATA2
LG L246WH Flatron 24"