A general overview of the different display methods and orientations explaining the pros and cons of each should go here
It is easier than ever to have a native set-up, but it isn't automatic, and particularly as there are many possible combinations of hardware, different solutions will be necessary. Almost all are documented on the forums.
For a detailed presentation of the different types of video rendering - ie: native scanlines vs scaled rendering (which includes arcade CRT vs standard LCD) - go to Arcade Controls post (in the Monitor/Video sub-forum) :
At the end of the following post is a decent example of 'scanlines' on a 27" monitor:
As well, one should read either or both of the following links before attempting a native display set-up: