First off, I've got to say thanks to the people on the BMR forums that have helped me out before (Especially Olin

) when I needed PC-related advice. It's been great and extremely helpful!
...on to my question,

.
Since I had 2 things I needed to ask (with a few extra sub-questions) and I REALLY don't like spamming with a million and seven threads, I'll just ask them both in one thread. I've been looking at TV tuners and sound cards lately, since I don't exactly need any peripherals or component upgrades, and decided I need to know a bit more about them before I go blindly buy one...
TV Tuners.
Not really much of a story as to why I'm looking at TV tuners, to be honest. My DVR is out of storage, I'd love the ability to watch and record TV on my PC, and if I can watch HDTV on my PC as well, awesome.
Haha... here's the problem: I don't know a single thing about TV Tuners. So I don't know what to look for in one, I don't know what brands to go with, and I don't know what specs (if any in particular) I need a tuner to have. So I have a few questions, and would gladly take recommendations on what to get.
A. What kind of input would I need to look for?
B. Is it possible to get a tuner that can play HD TV?
C. If a tuner can play HD TV, what kind of input/specs would I need to look for to make sure?
I don't have a big sound system or anything (Hell, I use a pair of $30 headphones) if that makes a difference.
I'd also need one that's certified for Vista (Since I'm on Windows 7, anything that works on Vista SHOULD work on 7 with a little tweaking if necessary)
Sound Cards:
I'm looking/leaning more towards getting a tuner first than I am a sound card, but I've noticed lately my onboard sounds kind of bad (I can't really explain it, to be honest.) so I'm looking at sound cards as well. Again, I sound like a complete idiot, but I don't know much/anything about sound cards either, so advice and recommendations would be great, again

.
Like I said, no fancy sound system or anything, but I'll end up getting better headphones later on (I've never been a big fan of huge speaker systems, especially since I'm in an apartment)
I've seen some sound cards that can do virtual 5.1 or 7.1 surround sound. Is it even worth it to aim for a sound card that can do that?
Also, it would need to have drivers/be certified for Vista (I'm pretty sure Creative mentioned they had some Windows 7 beta drivers being tested).
I figured since this forum doesn't have a lot of threads, and audio/video basically falls under a Home Theater category, the thread would fit here. If I posted in the wrong forum, I apologize.
Thanks!