A HD recording capable TV tuner card suggestion?

I know there are some Aver Media cards, both internal and external, which will help me recording HD stuffs from AirTel. But I'm confused which one to buy. I probably will like external, because it will record with the PC being turned on right? And how about the recording quality, is it good? All providers give 1080i, so I guess 1080p isn't needed right? Also I would like to have an external storage support, so that I can connect my Pen drive or PHDD to it.

Thanks in advance.