Recording Digital TV is not that simple with new TV tuners since there is macrovision protection enabled for DTH services. (My Experience with TATA SKY) so you only have one choice and that is to use RF connector to record.
In that I would recommend you
Leadtek Winfast DTV 1800 H or DTV 2000 H
If you can afford go for monster, DTV 3200 H
Here are links to buy these
*www.theitdepot.com/details-Leadtek+WinFast+Hybrid+TV+Tuner+(PxDVR3200+H)_C53P5427.html
*www.theitdepot.com/details-Leadtek+WinFast+Hybrid+TV+Tuner+(DTV2000+H+Plus)_C53P5428.html
*www.theitdepot.com/details-Leadtek+WinFast+Hybrid+TV+Tuner+(DTV1800+H)_C53P5429.html