For most using Hauppage DVB-T (Digital Freeview TV) Cards the 1.2 verson of WinTV 7 is downloadable from the Hauppage site and works with Windows 7 RTM.
Earlier versions gave problems such as not being able to tune in digital channels etc. I'm using the HVR 1110 card (67XX).
Whilst Windows Media Center is OK for TV channels my niggle is that if you use a COMPOSITE input to this card such as Camcorders, TV senders etc (I use a sender to transmit signal from my satellite box) Windows Media centre woon't do it --it always asks for some stinking remote ?????.
However WinTV has now been fixed
(note this is for Windows RTM only -- I'm running X-64) -- I haven't tried the application on earlier versions of Windows 7.