Even if you you set the resolution to the tv, it will not look near as good. Computer monitor pixels are alot smaller than tv pixels. (If they are even called pixels)
So no matter what, unless you have a plasma screen, it will not look as good as a computer monitor.
The only reason I hook up my computer to my tv is to watch divx movies. Compressed Divx movies look alot clearer on a television than a computer monitor.