Here are my suggestions for you. htpc's don't need to be expensive.
AMD's A8-5500 APU:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
or
A10-5700 APU:
http://www.newegg.com/Product/Product.aspx?Item=N82E168... will be perfect for an HTPC, especially since it's just move watching. Do they like or plan to watch blue ray? Might have to get a good blue-ray optical drive then.
http://www.tomshardware.com/reviews/windows-8-dvd-playb... denotes windows 8 compatibility.
It seems windows 7 is still best for HTPC.
Yes windows 7 is better since windows 8 doesn't have blueray compatibility in it it's media-center without 3rd party software. Or even dvd playback for it's media player. Media Player classic is free works for both though. (it should be able to play blueray..) Realplayer works as well. And other software..
I think this would be a good case:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Cheap, but good for HTPC. Have to clean it of dust at least once a month like any computer..
4gb ram is fine for a htpc. If that htpc will be a hand me down though to someone in the future, maybe 8gb.. lol
Heres a good ram:
http://www.newegg.com/Product/Product.aspx?Item=N82E168... Cheap too.
No clue about sound cards. I've heard it's subjective. They generally do sound better, if you get a good one, but it takes a good sound system to use them well. (continued in motherboard section of post lolo)
Western digital hardrives appear to be on sale right now, so you're in luck..
Here is a cheap one:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
A better one:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The 2tb version of ^ one:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
WD black has good reviews but is expensive..
And here's another one of a different version, looks good for a htpc (lower power, made for 24/7 use):
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Here's a cheap (but slower) 2TB hard drive that uses low power:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
wow.. so many hard drives to choose from xO
Media remote is a question mark for me too. I dunno about that.
Do you need a Tv Tuner? So you can record or watch TV and use computer like a DVR?
For your motherboard do you need USB 3.0? If so then you should get a mother board with a chipset of at least A75 for FM2. It has usb 3.0 built in.
This looks like a good motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
As for the connections you need to make your system happen, I don't know what you need (lol). This does have an HDMI input though, big TVs should have that as well.
As for it's onboard audio here is a thread about it:
http://www.overclockers.com/forums/showthread.php?t=706...
It seems like it has good sound.
Here is a thread about sound cards though:
http://www.tomshardware.com/forum/306650-30-asus-xonar-...
They beg to differ lol xonar and asus I guess for sound cards. Annoying software is annoying..?
If you choose these:
APU:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Case:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
RAM:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Harddrive:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It will cost you $368.
A good sound card is probably, $20-40. And you could get a better CPU cooler for $20-40 so that temps aren't a worry. A bigger case for $20-40 more maybe. And the better APU for $20 more of course. A good blueray drive can cost $50-70. Regular dvd write/rewrite drives can cost as low as $20.
You might also need better thermal paste:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Since the price is low you might be able to afford an SSD to put windows on. It will speed up daily activity. Movies would be loaded and stored from the HDD though. (if digital movies) ($100-130 for samgsung 830 126Gb)
You can buy windows 7 home oem
http://www.amazon.com/Windows-Premium-64bit-System-Buil....
Or this a 3 pack "family upgrade":
http://www.amazon.com/Microsoft-Windows-Premium-Upgrade...
Thats all I can think of right now. harhar
Edit: thought of something else to add