is it better to find a tv that has a TV input on the back of it….

or is it ok to use a converter cable that goes from a regular pc connection down to a HDMI connection and then plug that into your LCD?

I dont want to lose any quality or speed or anything since I will be using a 42 inch LCD to play PC video games on.
I mean PC input not TV input.

I have my xbox360,ps3,and dish network (hd reciever)all hooked up with hdmi cables..(I have 3 hdmi imputs)..my xbox360,ps3 work great..no problems..the problem is when I turn on my dish network reciever..I get a great hd picture but no sound..but when I turn on my xbox360 or my ps3..and switch back to my dish network I get sound..really odd?..its not the hdmi cable I have tried various ones..any help would be great
okay I put it on pcm only…what should I use line mode..or rf mode..I have no idea what those mean lol..

Is there any way that I may possibly be able to fix this myself? Most are just small scratches but there is one long line of the black film missing and rather than pay someone to fix it, is it possible to buy the film and replace it myself??