Okay, this is going to have a few questions in it, so I'm not sure if this is the right section, but....

1.) I am looking to set up a media PC for viewing online content but also to use as a DVR for cable television. I have charter cable. I was wondering what TV Tuner card (or what type) I would need as I understand it needs a certain kind to decrypt cable signals.
2.) How "useable" is the interface for setting up scheduled recordings (does it depend on the card? or maybe distro?)? I want it to be useable by my mom who has very little technical know how.
3.) What distro would you recommend (or even windows if need be) for this? Once again, it should be easy to use for my mom (setting it up can be difficult, I have no issues with that.)
4.) My tentative rig is going to be a 2.9ghz dual core with 2gb of ddr2 RAM and a 1GB vid ddr2 RAM pcie 2.0 card. 1TB hard drive and a dvd burner drive. Do you think this will do the trick (minus lacking the tuner card of course)?
5.) Is there anything that seems to be missing? If so, what?

Thank you so much if you made it this far xD. This is my first build for something intended as a DVR and I'm unsure of the hardware that I may need and can't find a very solid answer online so far. If you can answer any of the above questions, it would be GREATLY appreciated.
Thanks!

http://www.mythtv.org/wiki/Video_capture_card

Ought to be a good start (actually the whole wiki...).

thanks for the response! I think I'll need a DVB-C card, but i don't see anything like that on tigerdirect. Does it seem like http://www.tigerdirect.com/applicati...198&CatId=4547 will work?

Also, it seems that almost any distro with a modern kernel and mythTV installed should work fine. Is this assumption correct? I'm not too worried about remotes working, but i hear there is pretty good support for those lately anyways.

Another good resource: http://www.linuxtv.org/

From that site I found a list of PCI cards and a list of PCI-E cards. I did not see the card you linked listed, but should give you more to look at.

Mythbuntu should take out a lot of the pain of setting up MythTV. Its an Ubuntu respin with all normal Ubuntu feature there just with MythTV there as defualt and a new UI designed for MythTV.

It dosen't have all the normal packages that ubuntu has but there just a sudo aptitude install away.

I tried mythbuntu out in a virtual machine. Assuming I make sure my card is compatible with it, it looks like it is a breeze to set up and seemed very user friendly!

I would like to add knoppmyth and mythdora to that list.
I've been a happy mythdora user for about 5 years now.

You will need a normal cable tuner if you got analog TV on the cable. If so, try the Hauppage PVR-500.
If you've got digital TV on the cable, you'd use a DVB-C card. Most cards out there only support free-to-air(cable) signals smartcards are usually not supported.

Be careful not to buy something that's not on the mythtv 'confimed' HCL.

Any distribution will work. It is not the distribution that matters for your setup. It is the PVR or DVR software that you pick depends how easy it is to use. MythTV is OK if you do not mind being force to download the TV guide in order to use it. XBMC is another, but GUI is not straight forward to use although it is better than MythTV. SageTV will probably be better of the three, but you have to pay for it which is not a bad thing if it works better for you and your mom.

If you use a nVidia graphics card that is capable of handling VDPAU, then you do not need to use a fast processor to do the decoding. These days you can get by using a slower processor even when decoding H.264 HD content. Though you will need a fast processor to handle Flash.

Just about any video capture card will work, but you have to find out what chip the video capture card uses before buying it or else it may not work. To ease setup to record and watch ATSC channels, use SiliconDust HDHomeRun. It works with Linux and other operating systems. Also you do not have to plug it into the computer, so other computers can access it while you are installing or when your DIY PVR box is off. To watch and record NTSC, I recommend to use a cable box or VCR to tune to the desire channel and send it through S-Video or composite to the video capture card because the NTSC tuner for most video capture cards is pathetic. This will cause some problems to record from the VCR or cable box because the cable box or VCR have to be set at the channel and be fixed there until the recording is done. The simplest way for your mom is just use a DVR or PVR instead making your own. If your mom is not technically educated as you are, a DIY PVR or DVR is not going be easy because it going to make you look stupid. If you are doing it for your self, then you can make your own DVR or PVR.

My wife is happy using MythTV and believe me that's saying something =)
Ditributions do matter, some are a DIY project, others almost work straight out of the box.
Therefore my comment on the HCL's, if it's supported the after install tasks usually are limited to tuning into your channels.
But please look around and choose what's right for you.