Creating High Res Images from Renderings?

[knight]

I know for me the larger you can make the rendering window on the screen the better the quality, when I send to layout the rendering is usually much larger than a typ. 24 x 36 page, then I just reduce it to fit wherever I want. if you want better than rendering, use ray-trace for that. also your video card is in play here, change to a bigger resolution if you can.

I know that this is an old thread but it has answered most of the questions that I've had regarding high resolution images but what is the highest quality that you can get using this method?