Perhaps, but i think we can manage.
To play video files (avi? DVD?) onboard graphics is sufficent. Some codecs like h.264 (aka Mpeg4) can benifit from having a seperate graphics card with hardware decoding (means it's not stressing your CPU).
To watch TV or record it on your computer is a different kettle of fish. You need a TV card for that, either digital, analouge or a hybrid that can do both. Digital means you get to watch digital channels, but won't be able to use a VCR or standalone DVD player. Analouge means you're stuck with either a digibox or analouge TV, hybrids do both but cost more.
These can either be USB sticks, USB standalone boxes or PCI cards. Most will come with a remote, some can be used with windows MCE.
Which one to buy? Pass, i've extensive experience with Hauppage who make good hardware but terrible software.