HTPC with Digital TV Help Please

Greetings all, i am on the edge of buying a new system in teh aim of building a HTPC (sky box blown up and bored).

My aim;
I want a HiDef HTPC, with PVR function. I want to be able to have a signal from my dish (HD) or maybe two!

What i know;
As far as building the system no problem been building since i was 12 (now in my 20s). I no i can choose xp MCE, Vista HP, or run a linux distro (i will choose the latter two tho but would appreciate advice on these)

What i dont know;
Digital signal, and channels i am not paying for sky just getting the free channels atm. (just as a note here i dont think i can get DVB although this may just be my tv aerial) so what channels can i get

Card?
I have looked at may cards, but struggle to find an ideal one due to the descriptions

Questions;

1. What is the best OS for a PVR HTPC?
2. If i were to subscribe to sky (to get more channels) can i do this on this system?
3. What card is the best (preferably PCI not PCIe as my wifi card is PCIe) for the following functions;

• singal or dual channel recordings
• lots of channels (at least ch 1-5)

Fingers tired of christmas typing now, cheers in advance and i hope you have all had a merry xmas and hope you all have a great new years and the new year brings good times....

....rant ends

1) depends on what your main use is, and how much time you want to put in. i personally use mythtv on linux, some people swear by windows packages
2) not without a sky box, legally anyway. sky channels are encrypted using a scheme called NDS, and your contract with sky stipulates using their set-top box to decrypt the signal. even if you go with this (and many do), thee's no way to get an unmolested digital unencrypted signal from a sky box - you'd have to capture an analog SD feed from it using a capture card
3) if you can get dvb-t in your area, go for a tried & trusted card like a nova-t. if you need satellite, a nova-s ought to work (but a card like a technotrend s-1500 would open options for foreign encrypted channels via a licensed decryption card).

in terms of channels, on dvb-t, you get whatever is broadcast your your nearest multiplex. for satellite, depends on the size and direction of your dish - with a leftover sky minidish, you ought to be able to get all these channels

cheers directhex

thats really annoying all i want is the expansion and ability to watch channel 4 and 5 without having to flip to terrestrial.

Just gonna have to get a sky plus box and scrap my idea another fun build was gettin excited about adding another computer to my den.

any one other ideas or loopholes????