I think the OPs question is not "what is a good board?" but instead "what makes a board good?" a very good question but unfortunately very difficult to answer. Really it comes down to the application of the hardware eg. gaming computer, budget build, server etc. and the price you can put on its application eg. mission critical, important or unimportant. Once you know clearly what application this hardware has it becomes easier to see how much of certain characteristics and what features you need.
Some things are easier to quantify such as form factor, number of pci slots, number of processors supported etc, some characteristics can be more difficult to quantify, such as performance, reliability and board layout and some things are impossible to quantify eg. personal taste regarding PCB colour.
So unfortunately the answer to "what makes a board good?" is "whatever you want/need/like"
I know this is not really the answer you were looking for but I'm sure that if you could provide us with answers to some of the questions I have outlined then we will be able to help further.
