Building An HTPC (Worth it for me?)

Hey all, I was considering building a HTPC because I always like the idea to have all my DVDs on a hardrive instead of have a BIG (really) compilation of DVDs.

Here's the thing. I want to replace my DVD player, so that's all good. But, I already have a good amplifier (Denon) and I also have the OrangeBox (Like a freebox or skybox...) because I'm tied with Orange - I'm living in France btw. Does this mean that with a TV-tuner card I can get the channels I paid for instead of using the OrangeBox to decode/unscramble my channels?

With all that being said what's most important is that this build is going to be cost effective. Is it?

Thx, Mojito

For the HTPC build, it's not difficult at all, and you can get a good build for any realistic budget. The majority of the people on these forums aren't in France though, and can't answer your other questions. I don't really know what an OrangeBox is, or how it really works since they don't exist here. Even if they are similar to our standard cable boxes in the US, they probably have different guidelines and regulations in France.