What is the recommended hardware/software that I need to install?
FYI, I am running Windows 7 on the HTPC
I'm familiar with Windows Media Center (Vista and 7), so I'll tell you what I am familiar with. There are also others available from the Linux world such as MythTV.
Besides the TV tuner card, I'd recommend that you purchase a MCE compatible remote and receiver if you don't have one already. MCE compatible remotes usually include wakeup support, so you can wake your PC if it goes into standby.
The software I use is
Media Center records the TV show. Lifextender then automatically grabs the recorded show and removes the commercials. If I haven't deleted a show after 2 weeks, MCEBuddy compresses that show so that I don't run out of space.
Right now, third party tools work better with Vista than with Windows 7. Lifextender does not work directly with the WTV files that Windows 7 produces, but there is a work-around at http://www.hack7mc.com/2009/03/cut-out-commercials-in-7mc-with.html.
How could I forget - http://www.codinghorror.com/blog/archives/001107.html
First, you'll need a TV tuner (or two) to receive the signal.
Second, a large fast hard drive - the largest and quickest with the highest data transfer rate you can afford.
It's difficult to make specific recommendations as a) I don't know what part of the world you're in and b) any hardware I recommend today could well be superseded tomorrow.
I've found some info on iViewCameras.co.uk which would seem to indicate that a 7200 rpm hard drive should be up to the job of recording video. Though I would think the Data Transfer Rate - 300 MBps in this case - would be more important.